Flame retardant polycarbonate compositions, methods of manufacture, and articles formed therefrom

ABSTRACT

A composition comprising: a first polycarbonate comprising a poly(siloxane-carbonate); a second polycarbonate different from the first polycarbonate; and optionally, a third polycarbonate different from the first and second polycarbonate; wherein the first polycarbonate is present in an amount effective to provide the siloxane units of in the first polycarbonate in an amount of at least 0.3 wt %, and the second polycarbonate is present in an amount effective to provide the bromine of the second polycarbonate in an amount of at least 7.8 wt %; and further wherein an article molded from the composition has an OSU integrated 2 minute heat release test value of less than 65 kW-min/m 2  and a peak heat release rate of less than 65 kW/m 2 , and an E662 smoke test Dmax value of less than 200.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/207,930, filed Aug. 11, 2011, which claims priority to IndiaPatent Application No. 920/DEL/2011, filed Mar. 31, 2011, the contentsof both applications being incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION

This disclosure generally relates to polycarbonate compositions, andmore particularly to flame retardant polycarbonate compositionscontaining specific combinations of polycarbonates.

Flame retardant (FR) polycarbonates and polycarbonate blends with UL V0and 5V A and B Underwriters Laboratories flammability ratings are widelyprepared and used, especially in a wide variety of electrical andelectronic applications. Conversely, only a very limited set ofpolycarbonates are used in aircraft and other transportationapplications particularly interior parts such as windows, partitionwalls, ceiling panels, cabinet walls, storage compartments, galleysurfaces, light panels, and the like. All of these applications havestringent flammability safety requirements that the polycarbonates mustmeet. Particular requirements include smoke density, flame spread, andheat release values. In the United States, Federal Aviation Regulation(FAR) Part 25.853 sets forth the airworthiness standards for aircraftcompartment interiors. The safety standards for aircraft andtransportation systems used in the United States include a smoke densitytest specified in FAR 25.5 Appendix F, Part V Amdt 25-116. Flammabilityrequirements include the “60 second test” specified in FAR 25.853(a)Appendix F, Part I, (a),1,(i) and the heat release rate standard(referred to as the OSU 65/65 standard) described in FAR F25.4 (FARSection 25, Appendix F, Part IV), or the French flame retardant testssuch as, NF-P-92-504 (flame spread) or NF-P-92-505 (drip test). Inanother example, the aircraft manufacturer Airbus has smoke density andother safety requirements set forth in ABD0031. In the event of a fire,components made from materials having these properties can increase theamount of time available for escape and provide for better visibilityduring a fire

Despite extensive investigation, current materials that meet these FARstandards could be further improved with respect to other properties.Thus, there is a perceived need for polysulfones having improved meltflow, improved ultraviolet (UV) stability, and improved lighttransmission. Siloxane-polyestercarbonates have low melt flow and goodcolor stability to indoor light, but may shift in color upon exposure toUV light. Certain polycarbonate-polyetherimide blends also have low meltflow, but can be difficult to formulate so as to provide bright whitecompositions.

In view of the current interior material safety standards, and inanticipation of more stringent standards in the future, materials thatexceed governmental and aircraft manufacturer flame safety requirementsare sought. Such materials should also advantageously maintain excellentphysical properties, such as toughness (high impact strength and highductility). It would be a further advantage if such materials could bemanufactured to be colorless and transparent. Still other advantageousfeatures include good processability for forming articles, smoothsurface finish, and light stability.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein is a polycarbonate composition comprising: a firstpolycarbonate comprising a poly(siloxane-carbonate) derived from atleast one dihydroxy aromatic containing polycarbonate unit, and at leastone polysiloxane bisphenol of formula (1), formula (2), or a combinationthereof

wherein R is each independently a C₁-C₃₀ hydrocarbon group, R² is eachindependently a C₇-C₃₀ hydrocarbon group, Ar is a C₆-C₃₀ aromatic group,and E has an average value of 5 to 200; a second polycarbonate differentfrom the first polycarbonate, the second polycarbonate comprisingbrominated carbonate units derived from2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol and carbonate unitsderived from at least one dihydroxy aromatic compound that is not2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol; and optionally a thirdpolycarbonate different from the first and second polycarbonate; whereinthe wt % of the first polycarbonate, second polycarbonate, and optionalthird polycarbonate sum to 100 wt %, the first polycarbonate is presentin an amount effective to provide the siloxane units of the firstpolycarbonate in an amount of at least 0.3 wt %, based on the sum of thewt % of the first, second, and optional third polycarbonate, and thesecond polycarbonate is present in an amount effective to provide thebromine of the second polycarbonate in an amount of at least 7.8 wt %,based on the sum of the wt % of the first, second, and optional thirdpolycarbonate; and further wherein an article molded or formed from thecomposition has an OSU integrated 2 minute heat release test value ofless than 65 kW-min/m² and a peak heat release rate of less than 65kW/m² as measured using the method of FAR F25.4, in accordance withFederal Aviation Regulation FAR 25.853 (d), and an E662 smoke test Dmaxvalue of less than 200 when tested at a thickness of 1.6 mm.

In another embodiment, a polycarbonate composition comprises: a firstpolycarbonate comprising a poly(siloxane-carbonate) derived from atleast one dihydroxy aromatic containing polycarbonate unit, and at leastone polysiloxane bisphenol of formula (1), formula (2), or a combinationthereof

wherein R is each independently a C₁-C₃₀ hydrocarbon group, Ar is aC₆-C₃₀ aromatic group, R² is each independently a C₇-C₃₀ hydrocarbongroup, and E has an average value of 5 to 75, specifically 5 to 15; asecond polycarbonate different from the first polycarbonate, the secondpolycarbonate comprising brominated carbonate units derived from2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol and carbonate unitsderived from at least one dihydroxy aromatic compound that is not2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol; and optionally a thirdpolycarbonate different from the first and second polycarbonate; whereinthe wt % of the first polycarbonate, second polycarbonate, and optionalthird polycarbonate sum to 100 wt %, the first polycarbonate is presentin an amount effective to provide the siloxane units of the firstpolycarbonate in an amount of at least 0.3 wt %, based on the sum of thewt % of the first, second, and optional third polycarbonate, and thesecond polycarbonate is present in an amount effective to providebromine in the second polycarbonate in an amount of at least 5.0 wt %,based on the sum of the wt % of the first, second, and optional thirdpolycarbonate; and further wherein an article molded from thecomposition has an OSU integrated 2 minute heat release test value ofless than 65 kW-min/m² and a peak heat release rate of less than 65kW/m² as measured using the method of FAR F25.4, in accordance withFederal Aviation Regulation FAR 25.853 (d), an E662 smoke test Dmaxvalue of less than 200 when tested at a thickness of 1.6 mm; and a hazeof less than 3% and a transmission greater than 85%, each measured usingthe color space CIE1931 (Illuminant C and a 2° observer), or accordingto ASTM D 1003-07 using illuminant C at a 0.062 inch (1.5 mm) thickness.

In another embodiment, a polycarbonate composition comprises: a firstpolycarbonate comprising a poly(siloxane-carbonate) derived from atleast one dihydroxy aromatic containing polycarbonate unit, and at leastone polysiloxane bisphenol of formula (1), formula (2), or a combinationthereof

wherein R is each independently a C₁-C₃₀ hydrocarbon group, Ar is aC₆-C₃₀ aromatic group, R² is each independently a C₇-C₃₀ hydrocarbongroup, and E in formula (1) and formula (2) has an average value of 10to 200; a brominated oligomer having a weight average molecular weight(Mw) of less than 15,000 Daltons as measured by gel permeationchromatography using polystyrene standards; and optionally an additionalpolycarbonate different from the first polycarbonate and the brominatedoligomer; wherein the wt % of the first polycarbonate, brominatedoligomer, and optional additional polycarbonate sum to 100 wt %, thefirst polycarbonate is present in an amount effective to provide thesiloxane units of the first polycarbonate in an amount of at least 0.4wt %, based on the sum of the wt % of the first, second, and optionalthird polycarbonate, and the brominated oligomer is present in an amounteffective to provide the bromine of the brominated oligomer in an amountof at least 7.8 wt %, based on the sum of the wt % of the firstpolycarbonate, brominated oligomer, and optional additionalpolycarbonate; and further wherein an article molded or formed from thecomposition has an OSU integrated 2 minute heat release test value ofless than 65 kW-min/m² and a peak heat release rate of less than 65kW/m² as measured using the method of FAR F25.4, in accordance withFederal Aviation Regulation FAR 25.853 (d), and an E662 smoke test Dmaxvalue of less than 200 when tested at a thickness of 1.6 mm.

Also described is a method of manufacture of the above-describedcompositions.

Articles comprising the above-described compositions are furtherdisclosed, as well as methods for the manufacture of the articles.

The above described and other features are exemplified by the followingDetailed Description and Examples.

DETAILED DESCRIPTION OF THE INVENTION

The inventors hereof have discovered that flame retardant, low smokepolycarbonate compositions can unexpectedly be obtained when twospecific polycarbonate compositions, neither of which meets certain lowsmoke standards and low heat release standards, are used in combination.In particular, certain polysiloxane block co-polycarbonates and certainbromine-containing polycarbonate compositions do not, by themselves,meet strict low smoke density standards when burned. However, specificcombinations of these two compositions can meet the low smoke densitystandards, and have very low heat release properties.

Achieving very low smoke density and very low flammability ratings areconflicting requirements. Halogenated, specifically brominated, flameretardants are used in polycarbonate compositions for theireffectiveness in improving flame spread properties and satisfying thestringent aircraft and rail interior flammability standards. Brominatedflame retardant additives, however, cause an increase in smoke when thesheet compositions are ignited. It is therefore surprising thatpolycarbonate compositions containing brominated flame retardants can beadded to a polysiloxane block co-polycarbonates and lower the smokedensity of the polysiloxane block co-polycarbonates.

The compositions can further have excellent impact strength and lowbrittleness (high ductility). In a further advantageous feature, thecombinations can be transparent. In another advantageous feature, thecompositions can have low density. Such compositions are especiallyuseful in the manufacture of flame retardant, low smoke polycarbonatesheets that can be used, for example, in aircraft, train, marine, orother transportation applications.

In an embodiment, the polycarbonate compositions contain a firstpolycarbonate (certain poly(siloxane-carbonate)s as further describedbelow), a second polycarbonate (certain brominated polycarbonates asfurther described below), and optionally a third polycarbonate differentfrom the first and the second polycarbonates, in amounts effective tosatisfy at least the smoke generation requirements of the AmericanSociety for Testing and Materials (ASTM) standard E662 (2006). This testmethod uses a photometric scale to measure the density of smokegenerated by the material during burning. Polycarbonate compositionssatisfying the smoke generation requirements for aircraft interiors havea smoke density of less than 200, in accordance with ASTM E662 (2006).For simplicity, this test can be referred to herein as the “smokedensity test.”

The first, second, and optional third polycarbonate are further selectedand used in amounts effective to satisfy the heat release ratesdescribed in FAR F25.4 (Federal Aviation Regulations Section 25,Appendix F, Part IV). Materials in compliance with this standard arerequired to have a 2-minute integrated heat release rate of less than orequal to 65 kilowatt-minutes per square meter (kW-min/m²) and a peakheat release rate of less than 65 kilowatts per square meter (kW/m²)determined using the Ohio State University calorimeter, abbreviated asOSU 65/65 (2 min/peak). In applications requiring a more stringentstandards, where a better heat release rate performance is called for, a2-minute integrated heat release rate of less than or equal to 55kW-min/m² and a peak heat release rate of less than 55 kW/m²(abbreviated as OSU 55/55) may be required.

Without being bound by theory, it is believed that the unexpectedcombination of low smoke density and low heat release values areobtained by careful selection and balancing of the absolute and relativeamounts of the first, second, and optionally third polycarbonates,including selecting an amount of first polycarbonate and the block sizeof the siloxane blocks in the first polycarbonate to provide at least0.3 weight percent (wt %) of siloxane units in the composition, andselecting the amount the second polycarbonate and the amount of brominein the second polycarbonate to provide at least 7.8 wt % of bromine inthe composition. The compositions therefore include amounts of the firstand second polycarbonates (or as described below, other brominatedoligomer) effective, i.e., sufficient to provide the desired amount ofsiloxane units and bromine, which in turn yields a composition havingthe an OSU integrated 2 minute heat release test value of less than 65kW-min/m² and a peak heat release rate of less than 65 kW/m² as measuredusing the method of FAR F25.4, in accordance with Federal AviationRegulation FAR 25.853 (d), and an E662 smoke test D_(max) value of lessthan 200 when tested at a thickness of 1.6 mm. In an embodiment, aneffective amount of the first polycarbonate copolymer is at least 5 wt%, based on the total weight of the first polycarbonate, secondpolycarbonate, and optional third polycarbonate. The precise amount ofthe first polycarbonate effective to provide at least 0.3 wt % of thesiloxane units, depends on the selected polycarbonate, the length of thesiloxane block, and desired properties, such as smoke density, heatrelease values, transparency, impact strength, and/or other desiredphysical properties. In general, to be effective, the smaller the blocksize and/or the lower the number of blocks in the first polycarbonate,the higher the fractional concentration of the first polycarbonate,based on the total weight of the first, second and optionally thirdpolycarbonates. Similarly, the lower the weight percent of bromine inthe second polycarbonate, the higher the fractional concentration of thesecond polycarbonate, based on the total weight of the first, second andoptionally third polycarbonate.

Thus in particular in this embodiment, the polycarbonate compositioncomprises at least 5 wt %, specifically 5 to 80 wt %, or at least 10 wt%, specifically 10 to 70 wt %, or at least 15 wt %, specifically 15 to60 wt % of the first poly(siloxane-carbonate), at least 20 wt %,specifically 20 to 95 wt % of the second brominated polycarbonate, inparticular a brominated polycarbonate derived from2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol(2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane (TBBPA) and carbonate unitsderived from at least one dihydroxy aromatic compound that is not TBBPA(“TBBPA copolymer”), and 0 to 70 wt % of the optional thirdpolycarbonate, based on the total weight of the first, second, andoptional third polycarbonate, i.e., the wt % of the first polycarbonate,second polycarbonate, and optional third polycarbonate sum to 100 wt %.The siloxane blocks have an average of 5 to 200 units, specifically 5 to100 units. At least 0.3 wt % of siloxane and at least 7.8 wt % ofbromine is present, each based on total weight of the firstpolycarbonate, second polycarbonate, and optional third polycarbonate.

Further in this embodiment, when the siloxane blocks have an average of25 to 75 units, specifically 25 to 50 units, and at least 2.0 wt % ofsiloxane is present based on total weight of the first polycarbonate,second polycarbonate, and optional third polycarbonate, excellenttoughness is obtained, in particular an article molded from thecomposition further has a room temperature notched Izod impact ofgreater than 500 J/m as measured according to ASTM D 256-10 at a 0.125inch (3.2 mm) thickness. The articles can further have 100% ductility.The amount of siloxane in the composition can be

Still further in this embodiment, when the siloxane units of the firstpolycarbonate are present in an amount of at least 2.0 wt % of the firstpolycarbonate and the composition has 35 to 50 wt % of the secondpolycarbonate (the TBBPA copolymer), each based on total weight of thefirst polycarbonate, second polycarbonate, and optional thirdpolycarbonate, and the siloxane blocks have an average length of 25 to50 units, excellent transparency can be obtained, in particular anarticle molded from this composition has a haze of less than 10% and atransmission greater than 70%, each measured using the color spaceCIE1931 (Illuminant C and a 2° observer), or according to ASTM D 1003(2007) using illuminant C at a 0.125 inch (3.2 mm) thickness.

Excellent transparency can also be obtained when the polycarbonatecomposition comprises the first polycarbonate in an amount effective toprovide at least 0.3 wt % of siloxane and the second polycarbonate in anamount effective to provide at least 5.0 wt % of bromine, each based ontotal weight of the first polycarbonate, second polycarbonate, andoptional third polycarbonate, and the siloxane blocks have an average of5 to 75, specifically 5 to 15 units. Effective amounts can be at least10 wt %, at least 30 wt %, specifically 30 to 80 wt % of the firstpolycarbonate, and at least 20 wt %, specifically at least 20 to 50 wt %of the second polycarbonate (the TBBPA copolymer), and 0 to 50 wt % ofthe optional third polycarbonate, each based on the total weight of thefirst, second, and optionally third polycarbonates. An article moldedfrom the composition has a haze less of less than 3% and a transmissiongreater than 85%, each measured using the color space CIE1931(Illuminant C and a 2° observer) or according to ASTM D 1003 (2007)using illuminant C at a 0.062 inch (1.5 mm) thickness.

In still other embodiments, it has been found that limiting the amountof the optional third polymer, together with use of specific first andsecond polycarbonates can produce compositions with advantageousproperties. In one such embodiment, the polycarbonate compositioncomprises the first polycarbonate (the poly(siloxane-carbonate)), thesecond polycarbonate (the TBBPA copolymer), and 8 to 12 wt % of thethird polycarbonate, wherein the wt % of the first polycarbonate, secondpolycarbonate, and third polycarbonate sum to 100 wt % based on thetotal weight of the first, second and optionally third polycarbonates.The siloxane blocks have an average of 20 to 85 units. At least 0.4 wt %of siloxane and at least 7.8 wt % of bromine is present, each based ontotal weight of the first polycarbonate, second polycarbonate, and thirdpolycarbonate. In an embodiment, the polycarbonate composition comprises5 to 60 wt % of the first poly(siloxane-carbonate) 30 to 60 wt % of thesecond polycarbonate (the TBBPA copolymer).

In an alternative embodiment, it has been found that other brominatedoligomers can be used in place of the TBBPA copolymer, such as otherbrominated polycarbonate oligomers or brominated epoxy oligomers. Inthis embodiment, the polycarbonate compositions contain the firstpoly(siloxane-carbonate), a brominated oligomer, and an optionaladditional polycarbonate different from the first polycarbonate and thebrominated oligomer. The optional additional polycarbonate can be thesame as the optional third polycarbonate described in the aboveembodiments. The first polycarbonate, the brominated oligomer, and theoptional additional polycarbonate are present in amounts effective toprovide at least 0.3 wt. %, or at least 0.4 wt % of siloxane and atleast 7.8 wt % of bromine, each based on total weight of the firstpolycarbonate, brominated oligomer, and additional polycarbonate, andthus satisfy at least the smoke density test and the heat release OSU65/65 test. In particular, the polycarbonate compositions comprise atleast 5 wt %, specifically 5 to 85 wt %, or at least 10 wt %,specifically 10 to 70 wt %, or at least 15 wt %, specifically 15 to 60wt %, of the first poly(siloxane-carbonate), at least 15 wt %,specifically at least 15 to 95 wt % of the brominated oligomer, and 0 to60 wt % of the optional additional polycarbonate, each based on thetotal weight of the first polycarbonate, brominated oligomer, andoptional additional polycarbonate. The siloxane blocks have an averageof 5 to 100 units.

While the smoke density and OSU tests demonstrate the ability of thepolycarbonate compositions described herein to comply with both thesmoke generation and heat release requirements for transportationcomponents, particularly aircraft or train interiors, any of theabove-described compositions can advantageously comply with otherrelated flammability and safety tests as described above.

The first, second, optional third, and optional additionalpolycarbonates, as well as the TBBPA copolymer and brominatedpolycarbonate oligomer have repeating structural carbonate units offormula (3):

wherein at least 60%, specifically at least 80%, and specifically atleast 90% of the total number of R¹ groups contains aromatic organicgroups and the balance thereof are aliphatic or alicyclic groups. Inparticular, use of aliphatic groups is minimized in order to maintainthe flammability performance of the polycarbonates. In an embodiment, atleast 70%, at least 80%, or 95 to 100% of the R¹ groups are aromaticgroups. In an embodiment, each R¹ is a divalent aromatic group, forexample derived from an aromatic dihydroxy compound of formula (4):HO-A¹-Y¹-A²-OH  (4)wherein each of A¹ and A² is independently a monocyclic divalent arylenegroup, and Y¹ is a single bond or a bridging group having one or twoatoms that separate A¹ from A². In an embodiment, one atom separates A¹from A². In another embodiment, when each of A¹ and A² is phenylene, Y¹is para to each of the hydroxyl groups on the phenylenes. Illustrativenon-limiting examples of groups of this type are —O—, —S—, —S(O)—,—S(O)₂—, —C(O)—, methylene, cyclohexyl-methylene,2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene,neopentylidene, cyclohexylidene, cyclopentadecylidene,cyclododecylidene, and adamantylidene. The bridging group Y¹ can be ahydrocarbon group, specifically a saturated hydrocarbon group such asmethylene, cyclohexylidene, or isopropylidene.

Included within the scope of formula (4) are bisphenol compounds offormula (5):

wherein each of R^(a) and R^(b) is independently a halogen atom or amonovalent hydrocarbon group; p and q are each independently integers of0 to 4; and X^(a) represents a single bond or one of the groups offormulas (6) or (7):

wherein each R^(c) and R^(d) is independently hydrogen, C₁₋₁₂ alkyl,C₁₋₁₂ cycloalkyl, C₇₋₁₂ arylalkyl, C₁₋₁₂ heteroalkyl, or cyclic C₇₋₁₂heteroarylalkyl, and R^(e) is a divalent C₁₋₁₂ hydrocarbon group. Inparticular, R^(c) and R^(d) are each the same hydrogen or C₁₋₄ alkyl,specifically the same C₁₋₃ alkyl, even more specifically, methyl.

In an embodiment, R^(c) and R^(d) taken together is a C₃₋₂₀ cyclicalkylene or a heteroatom-containing C₃₋₂₀ cyclic alkylene comprisingcarbon atoms and heteroatoms with a valency of two or greater. Thesegroups can be in the form of a single saturated or unsaturated ring, ora fused polycyclic ring system wherein the fused rings are saturated,unsaturated, or aromatic. A specific heteroatom-containing cyclicalkylene group comprises at least one heteroatom with a valency of 2 orgreater, and at least two carbon atoms. Heteroatoms in theheteroatom-containing cyclic alkylene group include —O—, —S—, and—N(Z)—, where Z is a substituent selected from hydrogen, hydroxy, C₁₋₁₂alkyl, C₁₋₁₂ alkoxy, or C₁₋₁₂ acyl.

In a specific embodiment, X^(a) is a substituted C₃₋₁₈ cycloalkylideneof formula (8):

wherein each R^(r), R^(p), R^(q), and R^(t) is independently hydrogen,halogen, oxygen, or C₁₋₁₂ organic group; I is a direct bond, a carbon,or a divalent oxygen, sulfur, or —N(Z)— wherein Z is hydrogen, halogen,hydroxy, C₁₋₁₂ alkyl, C₁₋₁₂ alkoxy, or C₁₋₁₂ acyl; h is 0 to 2, j is 1or 2, i is an integer of 0 or 1, and k is an integer of 0 to 3, with theproviso that at least two of R^(r), R^(p), R^(q), and R^(t) takentogether are a fused cycloaliphatic, aromatic, or heteroaromatic ring.It will be understood that where the fused ring is aromatic, the ring asshown in formula (8) will have an unsaturated carbon-carbon linkagewhere the ring is fused. When k is 1 and i is 0, the ring as shown informula (8) contains 4 carbon atoms, when k is 2, the ring as showncontains 5 carbon atoms, and when k is 3, the ring contains 6 carbonatoms. In an embodiment, two adjacent groups (e.g., R^(q) and R^(t)taken together) form an aromatic group, and in another embodiment, R^(q)and R^(t) taken together form one aromatic group and R^(r) and R^(p)taken together form a second aromatic group.

When k is 3 and i is 0, bisphenols containing substituted orunsubstituted cyclohexane units are used, for example bisphenols offormula (9):

wherein R^(f) is each independently hydrogen, C₁₋₁₂ alkyl, or halogen;and R^(g) is each independently hydrogen or C₁₋₁₂ alkyl. Thesubstituents can be aliphatic or aromatic, straight chain, cyclic,bicyclic, branched, saturated, or unsaturated. Suchcyclohexane-containing bisphenols, for example the reaction product oftwo moles of a phenol with one mole of a hydrogenated isophorone, areuseful for making polycarbonate polymers with high glass transitiontemperatures and high heat distortion temperatures. Cyclohexylbisphenol-containing polycarbonates, or a combination comprising atleast one of the foregoing with other bisphenol polycarbonates, aresupplied by Bayer Co. under the APEC® trade name.

Other useful dihydroxy compounds having the formula HO—R¹—OH includearomatic dihydroxy compounds of formula (10):

wherein R^(h) is each independently a halogen atom, a C₁₋₁₀ hydrocarbylsuch as a C₁₋₁₀ alkyl group, a halogen substituted C₁₋₁₀ hydrocarbylsuch as a halogen-substituted C₁₋₁₀ alkyl group, and h is 0 to 4. Thehalogen is usually bromine.

Some illustrative examples of dihydroxy compounds include the following:4,4′-dihydroxybiphenyl, 1,6-dihydroxynaphthalene,2,6-dihydroxynaphthalene, bis(4-hydroxyphenyl)methane,bis(4-hydroxyphenyl)diphenylmethane,bis(4-hydroxyphenyl)-1-naphthylmethane, 1,2-bis(4-hydroxyphenyl)ethane,1,1-bis(4-hydroxyphenyl)-1-phenylethane,2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane,bis(4-hydroxyphenyl)phenylmethane,2,2-bis(4-hydroxy-3-bromophenyl)propane,1,1-bis(hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane,1,1-bis(4-hydroxyphenyl)isobutene,1,1-bis(4-hydroxyphenyl)cyclododecane,trans-2,3-bis(4-hydroxyphenyl)-2-butene,2,2-bis(4-hydroxyphenyl)adamantine,alpha,alpha′-bis(4-hydroxyphenyl)toluene,bis(4-hydroxyphenyl)acetonitrile,2,2-bis(3-methyl-4-hydroxyphenyl)propane,2,2-bis(3-ethyl-4-hydroxyphenyl)propane,2,2-bis(3-n-propyl-4-hydroxyphenyl)propane,2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane,2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,2,2-bis(3-allyl-4-hydroxyphenyl)propane,2,2-bis(3-methoxy-4-hydroxyphenyl)propane,2,2-bis(4-hydroxyphenyl)hexafluoropropane,1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene,1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene,1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene,4,4′-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycolbis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether,bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide,bis(4-hydroxyphenyl)sulfone, 9,9 to bis(4-hydroxyphenyl)fluorine,2,7-dihydroxypyrene,6,6′-dihydroxy-3,3,3′,3′-tetramethylspiro(bis)indane (“spirobiindanebisphenol”), 3,3-bis(4-hydroxyphenyl)phthalide,2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene,2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine,3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and2,7-dihydroxycarbazole, resorcinol, substituted resorcinol compoundssuch as 5-methyl resorcinol, 5-ethyl resorcinol, 5-propyl resorcinol,5-butyl resorcinol, 5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumylresorcinol, 2,4,5,6-tetrafluoro resorcinol, 2,4,5,6-tetrabromoresorcinol, and the like; catechol; hydroquinone; and substitutedhydroquinones such as 2-methyl hydroquinone, 2-ethyl hydroquinone,2-propyl hydroquinone, 2-butyl hydroquinone, 2-t-butyl hydroquinone,2-phenyl hydroquinone, 2-cumyl hydroquinone, 2,3,5,6-tetramethylhydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone, 2,3,5,6-tetrafluorohydroquinone, 2,3,5,6-tetrabromo hydroquinone, and the like.Combinations comprising at least one of the foregoing dihydroxycompounds can be used.

Specific examples of bisphenol compounds that can be represented byformula (3) include 1,1-bis(4-hydroxyphenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane(bisphenol A or BPA), 2,2-bis(4-hydroxyphenyl)butane,2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane,1,1-bis(4-hydroxyphenyl)n-butane,2,2-bis(4-hydroxy-1-methylphenyl)propane,1,1-bis(4-hydroxy-t-butylphenyl)propane,3,3-bis(4-hydroxyphenyl)phthalimidine,2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (PPPBP), and1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC). Combinationscomprising at least one of the foregoing dihydroxy compounds can also beused.

“Polycarbonate” as used herein includes homopolycarbonates, copolymerscomprising different R¹ moieties in the carbonate (referred to herein as“copolycarbonates”), and copolymers comprising carbonate units and othertypes of polymer units, such as siloxane units or ester units. In aspecific embodiment, the polycarbonate is a linear homopolymer orcopolymer comprising units derived from bisphenol A, in which each of A¹and A² is p-phenylene and Y¹ is isopropylidene in formula (4). Morespecifically, at least 60%, particularly at least 80% of the R¹ groupsin the polycarbonate homopolymer or copolymer are derived from bisphenolA.

The first polycarbonate is a copolymer comprising carbonate units offormula (3) and blocks of siloxane units, i.e., apoly(siloxane-co-carbonate), referred to herein as a“poly(siloxane-carbonate).” The polysiloxane contains blocks of units offormula (11):

wherein R is each independently a C₁-C₃₀ hydrocarbon group, specificallya C₁₋₁₃ alkyl group, C₂₋₁₃ alkenyl group, C₃₋₆ cycloalkyl group, C₆₋₁₄aryl group, C₇₋₁₃ arylalkyl group, or C₇₋₁₃ alkylaryl group. Theforegoing groups can be fully or partially halogenated with fluorine,chlorine, bromine, or iodine, or a combination comprising at least oneof the foregoing. Combinations of the foregoing R groups can be used inthe same copolymer. In an embodiment, the polysiloxane comprises Rgroups that have minimum hydrocarbon content. In a specific embodiment,R is each the same and is a methyl group. In an embodiment, the siloxaneblocks are atactic, isotactic, or syndiotactic. In an embodiment, thetacticity of the siloxane can affect the effective amount of eachpolycarbonate copolymer used.

The average value of E in formula (12) can vary as described in theindividual embodiments above, from 5 to 200. In an embodiment, E has anaverage value of 5 to 100, to 100, 10 to 50, 25 to 50, or 35 to 50. Inanother embodiment, E has an average value of 5 to 75, specifically 5 to15, specifically 5 to 12, more specifically 7 to 12. The polysiloxaneunits can be

In an embodiment, polydiorganosiloxane units are derived frompolysiloxane bisphenols of formula (1):

wherein E is as defined above; each R can be the same or different, andis as defined above; and each Ar can be the same or different, and is asubstituted or unsubstituted C₆₋₃₀ arylene group, wherein the bonds aredirectly connected to an aromatic moiety. The Ar groups in formula (1)can be derived from a C₆₋₃₀ dihydroxy aromatic compound, for example adihydroxy aromatic compound of formula (4), (5), (8), (9), or (10)above. Combinations comprising at least one of the foregoing dihydroxyaromatic compounds can also be used. Illustrative examples of dihydroxyaromatic compounds are resorcinol (i.e., 1,3-dihydroxybenzene),4-methyl-1,3-dihydroxybenzene, 5-methyl-1,3-dihydroxybenzene,4,6-dimethyl-1,3-dihydroxybenzene, 1,4-dihydroxybenzene,1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane,2,2-bis(4-hydroxyphenyl)octane, 1,1-bis(4-hydroxyphenyl)propane,1,1-bis(4-hydroxyphenyl)n-butane,2,2-bis(4-hydroxy-1-methylphenyl)propane,1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl sulfide), and1,1-bis(4-hydroxy-t-butylphenyl)propane. Combinations comprising atleast one of the foregoing dihydroxy compounds can also be used. In anembodiment, the dihydroxy aromatic compound is unsubstituted, or is notsubstituted with non-aromatic hydrocarbon-containing substituents suchas alkyl, alkoxy, or alkylene substituents.

In a specific embodiment, where Ar is derived from resorcinol, thepolydiorganosiloxane repeating units are derived from polysiloxanebisphenols of formula (12):

or, where Ar is derived from bisphenol-A, from polysiloxane bisphenolsof formula (13):

wherein E is as defined above.

In another embodiment, polydiorganosiloxane units are derived frompolysiloxane bisphenols of formula (2):

wherein R and E are as described above, and each R² is independently adivalent C₁₋₃₀ alkylene or C₇₋₃₀ arylene-alkylene, and wherein thepolymerized polysiloxane unit is the reaction residue of itscorresponding dihydroxy aromatic compound. In a specific embodiment,where R² is C₇₋₃₀ arylene-alkylene, the polydiorganosiloxane units arederived from polysiloxane bisphenols of formula (14):

wherein R and E are as defined above. R³ is each independently adivalent C₂₋₈ aliphatic group. Each M can be the same or different, andcan be a halogen, cyano, nitro, C₁₋₈ alkylthio, C₁₋₈ alkyl, C₁₋₈ alkoxy,C₂₋₈ alkenyl, C₂₋₈ alkenyloxy group, C₃₋₈ cycloalkyl, C₃₋₈ cycloalkoxy,C₆₋₁₀ aryl, C₆₋₁₀ aryloxy, C₇₋₁₂ arylalkyl, C₇₋₁₂ arylalkoxy, C₇₋₁₂alkylaryl, or C₇₋₁₂ alkylaryloxy, wherein each n is independently 0, 1,2, 3, or 4.

In an embodiment, M is bromo or chloro, an alkyl such as methyl, ethyl,or propyl, an alkoxy such as methoxy, ethoxy, or propoxy, or an arylsuch as phenyl, chlorophenyl, or tolyl; R³ is a dimethylene,trimethylene or tetramethylene group; and R is a C₁₋₈ alkyl, haloalkylsuch as trifluoropropyl, cyanoalkyl, or aryl such as phenyl,chlorophenyl or tolyl. In another embodiment, R is methyl, or acombination of methyl and trifluoropropyl, or a combination of methyland phenyl. In still another embodiment, M is methoxy, n is 0 or 1, R³is a divalent C₁₋₃ aliphatic group, and R is methyl.

In a specific embodiment, the polydiorganosiloxane units are derivedfrom a polysiloxane bisphenol of formula (15):

wherein E is as described above.

In another specific embodiment, the polydiorganosiloxane units arederived from polysiloxane bisphenol of formula (16):

wherein E is as defined above.

Dihydroxy polysiloxanes can be made by functionalizing a substitutedsiloxane oligomer of formula (17):

wherein R and E are as defined in formula (11), and Z is H, halogen (Cl,Br, or I), or carboxylate, such as acetate, formate, benzoate, and thelike. In an embodiment where Z is H, compounds of formula (20) can beprepared by platinum catalyzed addition with an aliphaticallyunsaturated monohydric phenol. Suitable aliphatically unsaturatedmonohydric phenols included, for example, eugenol, 2-allylphenol,4-allylphenol, 4-allyl-2-methylphenol, 4-allyl-2-phenylphenol,4-allyl-2-bromophenol, 4-allyl-2-t-butoxyphenol, 4-phenyl-2-allylphenol,2-methyl-4-propenylphenol, 2-allyl-4,6-dimethylphenol,2-allyl-4-bromo-6-methylphenol, 2-allyl-6-methoxy-4-methylphenol, and2-allyl-4,6-dimethylphenol. Combinations comprising at least one of theforegoing can also be used. Where Z is halogen or carboxylate,functionalization can be accomplished by reaction with a dihydroxyaromatic compound of formulas (4), (5), (6), (7), (8), (9), and (10), ora combination comprising at least one of the foregoing dihydroxyaromatic compounds. In an embodiment, compounds of formula (13) can beformed from an alpha,omega-bisacetoxypolydiorganosiloxane and adihydroxy aromatic compound under phase transfer conditions.

The relative amount of carbonate and siloxane units in thepoly(siloxane-carbonate) will depend on the desired properties, and arecarefully selected using the guidelines provided herein. In particular,as mentioned above, the poly(siloxane-carbonate) is selected to have acertain average value of E, and is selected and used in amount effectiveto provide the desired wt % of siloxane units in the composition. In anembodiment, the poly(siloxane-carbonate) can comprise siloxane units inan amount of 0.3 to 30 weight percent (wt %), specifically 0.5 to 25 wt%, or 0.5 to 15 wt %, or even more specifically 0.7 to 8 wt %, or 0.7 to7 wt %, based on the total weight of the poly(siloxane-carbonate), withremainder being carbonate units, and with the proviso that the siloxaneunits are provided by polysiloxane units covalently bonded in thepolymer backbone of the polycarbonate-polysiloxane copolymer.

In an embodiment, the poly(siloxane-carbonate) comprises units derivedfrom polysiloxane bisphenols (14) as described above, specificallywherein M is methoxy, n is 0 or 1, R³ is a divalent C₁₋₃ aliphaticgroup, and R is methyl, still more specifically a polysiloxane bisphenolof formula (15) or (16). In these embodiments, E can have an averagevalue of 8 to 100, wherein the siloxane units are present in an amountof 0.3 to 25 wt % based on the total weight of thepoly(siloxane-carbonate); or, in other embodiments, E can have anaverage value of 25 to 100, wherein the siloxane units are present in anamount of 5 to 30 wt % based on the total weight of thepoly(siloxane-carbonate); or E can have an average value of 30 to 50, or40 to 50, wherein the siloxane units are present in an amount of 4 to 8wt % based on the total weight of the poly(siloxane-carbonate); or E canhave an average value of 5 to 12, wherein the siloxane units are presentin an amount of 0.5 to 7 wt % based on the total weight of thepoly(siloxane-carbonate).

1. In some embodiments a combination of two or more differentpoly(siloxane) copolymers, in particular two or more differentpoly(siloxane-carbonate)s are used to obtain the desired properties. Thepoly(siloxane) copolymers can differ in one or more of a property (e.g.,polydispersity or molecular weight) or a structural feature (e.g., thevalue of E, or the number of blocks of E. The additional polymer neednot be a poly(siloxane-carbonate), but can be a copolymer having (a) afirst repeating unit, and (b) a poly(siloxane) block unit having theformula:

wherein R is each independently a C₁-C₃₀ hydrocarbon group, and E has anaverage value of 5 to 200, wherein the first repeating unit is, forexample an imide, a etherimide, an ester, a arylene ether, an aryleneether ketone, an arylene ether sulfone, an arylene ether ketone, and thelike. For example, a poly(siloxane-carbonate) having a relatively lowerweight percent (e.g., 3 to 10 wt %, or 6 wt %) of relatively longerlength (E having an average value of 30-60) can provide a composition oflower colorability, whereas a poly(siloxane-carbonate) having arelatively higher weight percent of siloxane units (e.g., 15 to 25 wt %,or 20 wt %) of the same length siloxane units, can provide better impactproperties. Use of a combination of these two poly(siloxane-carbonate)scan provide a compostion having both good colorability and impactproperties. Similarly, a poly(siloxane-carbonate) can be used with apoly(siloxane-etherimide) to improve impact.

The first polycarbonate, i.e., the poly(siloxane-carbonate is used witha second, brominated polycarbonate or a brominated oligomer. The secondpolycarbonate is a specific brominated polycarbonate, i.e., apolycarbonate containing brominated carbonate units derived from2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol (TBBPA) and carbonateunits derived from at least one dihydroxy aromatic compound that is notTBBPA. The dihydroxy aromatic compound can be one of formula (5), (6),(7), (8), (9), or (10). In a specific embodiment the dihydroxy aromaticcompound is of formula (5), more specifically dihydroxy aromaticcompound (5) containing no additional halogen atoms. In an embodiment,the dihydroxy aromatic compound is Bisphenol-A.

The relative ratio of TBBPA to the dihydroxy aromatic compound used tomanufacture the TBBPA copolymer will depend in some embodiments on theamount of the TBBPA copolymer used and the amount of bromine desired inthe polycarbonate composition. In an embodiment, the TBBPA copolymer ismanufactured from a composition having 30 to 70 wt % of TBBPA and 30 to70 wt % of the dihydroxy aromatic compound, specifically Bisphenol-A, orspecifically 45 to 55 wt % of TBBPA and 45 to 55 wt % of the dihydroxyaromatic compound, specifically bisphenol-A. In an embodiment, no othermonomers are present in the TBBPA copolymer.

Combinations of different TBBPA copolymers can be used. Specifically, aTBBPA copolymer can be used having phenol endcaps. Also specifically, aTBBPA carbonate can be used having 2,4,6-tribromophenol endcaps can beused.

The TBBPA copolymers can have an Mw from 18,000 to 30,000 Daltons,specifically 20,000 to 30,000 Daltons as measured by gel permeationchromatography (GPC) using polycarbonate standards.

Alternatively, the first poly(siloxane-carbonate) is used with abrominated oligomer. Thus, instead of a TBBPA copolymer as the secondpolycarbonate, a brominated oligomer having an Mw of 18,000 Daltons orless is used. The term “brominated oligomer” is used herein forconvenience to identify a brominated compound comprising at least tworepeat units with bromine substitution, and having an Mw of less than18,000 Daltons. The brominated oligomer can have an Mw of 1000 to 18,000Daltons, specifically 2,000 to 15,000 Daltons, and more specifically3,000 to 12,000 Daltons.

In certain embodiments, the brominated oligomer has a bromine content of40 to 60 wt %, specifically 45 to 55 wt %, more specifically 50 to 55 wt%. The specific brominated oligomer and the amount of brominatedoligomer are selected to provide at least 7.8 wt % bromine, specifically7.8 to 14 wt % bromine, more specifically 8 to 12 wt % bromine, eachbased on the total weight of first polycarbonate, the brominatedoligomer, and the optional additional polycarbonate.

The brominated oligomer can be a brominated polycarbonate oligomerderived from brominated aromatic dihydroxy compounds (e.g., brominatedcompounds of formula (3)) and a carbonate precursor, or from acombination of brominated and non-brominated aromatic dihydroxycompounds, e.g., of formula (3), and a carbonate precursor. Brominatedpolycarbonate oligomers are disclosed, for example, in U.S. Pat. No.4,923,933, U.S. Pat. No. 4,170,711, and U.S. Pat. No. 3,929,908.Examples of brominated aromatic dihydroxy compounds include2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane,bis(3,5-dibromo-4-hydroxyphenyl)menthanone, and2,2′,6,6′-tetramethyl-3,3′,5,5′-tetrabromo-4,4′-biphenol. Examples ofnon-brominated aromatic dihydroxy compounds for copolymerization withthe brominated aromatic dihydroxy compounds include Bisphenol-A,bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane,4,4-bis(4-hydroxyphenyl)heptane, and(3,3′-dichloro-4,4′-dihydroxydiphenyl)methane. Combinations of two ormore different brominated and non-brominated aromatic dihydroxycompounds can be used. If a combination of aromatic dihydroxy compoundsis used, then the combinations can contain 25 to 55 mole percent of thebrominated aromatic dihydroxy compounds and 75 to 65 mole percent of anon-brominated dihydric phenol. Branched brominated polycarbonateoligomers can also be used, as can compositions of a linear brominatedpolycarbonate oligomer and a branched brominated polycarbonate oligomer.Combinations of different brominated copolycarbonate oligomers can beused. Various endcaps can be present, for example polycarbonates havingphenol endcaps or 2,4,6-tribromophenol endcaps can be used.

Other types of brominated oligomers can be used, for example brominatedepoxy oligomers. Examples of brominated epoxy oligomers include thosederived from Bisphenol-A, hydrogenated Bisphenol-A, Bisphenol-F,Bisphenol-S, novolak epoxies, phenol novolac epoxies, cresol novolacepoxies, N-glycidyl epoxies, glyoxal epoxies dicyclopentadiene phenolicepoxies, silicone-modified epoxies, and epsilon-caprolactone modifiedepoxies. Combinations of different brominated epoxy oligomers can beused. Specifically, a tetrabromobisphenol-A epoxy be used, having2,4,6-tribromophenol endcaps. An epoxy equivalent weight of 200 to 3000can be used.

In the polycarbonate compositions comprising the first polycarbonate(the poly(siloxane-carbonate)) and the second, brominated polycarbonate(the TBBPA copolymer), an optional third polycarbonate can be presentthat is not same as the first poly(siloxane-carbonate) or the secondTBBPA copolymer). Specifically, the third polycarbonate does not containsiloxane units or bromine. In the alternative embodiments of thepolycarbonate compositions comprising the first polycarbonate (thepoly(siloxane-carbonate)) and a brominated oligomer, an additionalpolycarbonate that is not the same as the first poly(siloxane-carbonate)or the brominated oligomer is present. Specifically, the additionalpolycarbonate does not contain siloxane units or bromine.

In some embodiments a combination of two or more different brominatedpolymers are used to obtain the desired properties. The brominatedpolymers can differ in one or more of a property (e.g., polydispersityor molecular weight) or a structural feature (e.g., the identity of therepeating units, the presence of copolymer units, or the amount ofbromine in the polymer). For example, two different TBBPA copolymers canbe used, or a combination of a TBBPA copolymer and a brominated epoxyoligomer. Of course, two or more different poly(siloxane) copolymers canbe used with two or more different brominated polymers.

The optional third polycarbonate and the additional polycarbonatecomprise units of formula (3) as described above, specifically whereinR¹ is derived from the dihydroxy aromatic compound (5) (6), (7), (8),(9), or (10), or a combination thereof, and more the specificallydihydroxy aromatic compound (5) containing no additional halogen atoms.In an embodiment, at least 60%, at least 80%, or at least 90% of the R¹units are Bisphenol-A units. In an embodiment, the optional thirdpolycarbonate is a homopolymer with Bisphenol-A carbonate units. Inanother embodiment, the additional polycarbonate is a homopolymer withBisphenol-A carbonate units.

It is also possible for the optional third polycarbonate or theadditional polycarbonate to contain units other than polycarbonateunits, for example ester units. Polycarbonate copolymers with esterunits, known as poly(ester-carbonate)s and polyester-polycarbonates areselected so as to not significantly adversely affect the desiredproperties of the polycarbonate composition, in particular low smokedensity and low heat release, as well as other properties such asstability to UV light. For example, aromatic ester units can diminishcolor stability of the polycarbonate composition during processing andwhen exposed to UV light. Aromatic ester units can also decrease themelt flow of the polycarbonate composition. On the other hand, thepresence of aliphatic ester units can diminish the heat release values.

When used, poly(ester-carbonate)s further contain, in addition torecurring carbonate chain units of formula (3), repeating units offormula (17):

wherein D is a divalent group derived from a dihydroxy compound, and canbe, for example, a C₂₋₁₀ alkylene group, a C₆₋₂₀ alicyclic group, aC₆₋₂₀ aryl, or a polyoxyalkylene group in which the alkylene groupscontain 2 to 6 carbon atoms, specifically 2, 3, or 4 carbon atoms. In anembodiment, D is a C₂₋₃₀ alkylene having a straight chain, branchedchain, or cyclic (including polycyclic) formula. In another embodiment,D is derived from an aromatic dihydroxy compound of formula (5) above.In another embodiment, D is derived from an aromatic dihydroxy compoundof formula (10) above. T in formula (17) is a divalent group derivedfrom a dicarboxylic acid, and can be, for example, a C₂₋₁₀ alkylenegroup, a C₆₋₂₀ alicyclic group, a C₆₋₂₀ alkyl aromatic group, or a C₆₋₂₀aromatic group. Examples of aromatic dicarboxylic acids that can be usedto prepare the polyester units include isophthalic or terephthalic acid,1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether,4,4′-bisbenzoic acid, and combinations comprising at least one of theforegoing acids. Acids containing fused rings can also be present, suchas in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids. Specificdicarboxylic acids are terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexane dicarboxylic acid, or combinationscomprising at least one of the foregoing. A specific dicarboxylic acidcomprises a combination of isophthalic acid and terephthalic acidwherein the weight ratio of isophthalic acid to terephthalic acid is100:0 to 0:100, or 99:1 to 1:99, or 91:9 to 2:98.

In another specific embodiment, D is a C₂₋₆ alkylene and T isp-phenylene, m-phenylene, naphthalene, a divalent cycloaliphatic group,or a combination comprising at least one of the foregoing.Alternatively, the polyester unit of the polyester-polycarbonate can bederived from the reaction of resorcinol with a combination ofisophthalic and terephthalic diacids (or derivatives thereof). Inanother specific embodiment, the polyester unit is derived from thereaction of Bisphenol-A with a combination of isophthalic acid andterephthalic acid. In any of the foregoing embodiments, thepolycarbonate units of the poly(ester-carbonate) are derived from acombination of resorcinol and bisphenol A in a molar ratio of resorcinolcarbonate units to bisphenol A carbonate units of 1:99 to 99:1,specifically 20:80 to 80:20. The molar ratio of ester units to carbonateunits in the copolymers can vary broadly, for example 1:99 to 99:1,specifically 10:90 to 90:10, more specifically 25:75 to 75:25, dependingon the desired properties of the final composition.

The first polycarbonates, optional third polycarbonates, and additionalpolycarbonates can have an Mw of 5,000 to 200,000, specifically 10,000to 100,000 grams per mole (g/mol), even more specifically 15,000 to60,000 g/mol, still more specifically 16,000 to 45,000 g/mol, asmeasured by gel permeation chromatography (GPC), using a crosslinkedstyrene-divinylbenzene column and calibrated to polycarbonatereferences. GPC samples are prepared at a concentration of 1 mg/ml, andare eluted at a flow rate of 1.5 ml/min.

Melt volume flow rate (often abbreviated “MVR”) measures the rate ofextrusion of a thermoplastic through an orifice at a prescribedtemperature and load. The polycarbonates can have an MVR, measured at300° C. under a load of 1.2 kg, of 0.1 to 200 cubic centimeters per 10minutes (cm³/10 min), specifically 1 to 100 cm³/10 min.

The first polycarbonates, optional third polycarbonates, and additionalpolycarbonates can be manufactured by interfacial polymerization or meltpolymerization processes. Although the reaction conditions forinterfacial polymerization can vary, a process generally involvesdissolving or dispersing an aromatic dihydroxy reactant in aqueouscaustic soda or potash, adding the resulting mixture to awater-immiscible solvent medium, and contacting the reactants with acarbonate precursor in the presence of a catalyst such as, for example,triethylamine or a phase transfer catalyst, under controlled pHconditions, e.g., 8 to 11. The most commonly used water immisciblesolvents include methylene chloride, 1,2-dichloroethane, chlorobenzene,toluene, and the like.

Carbonate precursors include, for example, a carbonyl halide such ascarbonyl bromide or carbonyl chloride, or a haloformate such as abishaloformates of a dihydric phenol (e.g., the bischloroformates ofbisphenol A, hydroquinone, or the like) or a glycol (e.g., thebishaloformate of ethylene glycol, neopentyl glycol, polyethyleneglycol, or the like). Combinations comprising at least one of theforegoing types of carbonate precursors can also be used. In anembodiment, an interfacial polymerization reaction to form carbonatelinkages uses phosgene as a carbonate precursor, and is referred to as aphosgenation reaction.

Among the phase transfer catalysts that can be used are catalysts of theformula (R³)₄Q⁺X, wherein each R³ is the same or different, and is aC₁₋₁₀ alkyl group; Q is a nitrogen or phosphorus atom; and X is ahalogen atom or a C₁₋₈ alkoxy or C₆₋₁₈ aryloxy group. phase transfercatalysts include, for example, [CH₃(CH₂)₃]₄NX, [CH₃(CH₂)₃]₄PX,[CH₃(CH₂)₅]₄NX, [CH₃(CH₂)₆]₄NX, [CH₃(CH₂)₄]₄NX, CH₃[CH₃(CH₂)₃]₃NX, andCH₃[CH₃(CH₂)₂]₃NX, wherein X is Cl⁻, Br⁻, a C₁₋₈ alkoxy group, or aC₆₋₁₈ aryloxy group. An effective amount of a phase transfer catalystcan be 0.1 to 10 wt % based on the weight of bisphenol in thephosgenation mixture. In another embodiment, an effective amount ofphase transfer catalyst can be 0.5 to 2 wt % based on the weight ofbisphenol in the phosgenation mixture.

Alternatively, melt polymerization processes can be used to make thepolycarbonates. Generally, in the melt polymerization process,polycarbonates can be prepared by co-reacting, in a molten state, thedihydroxy reactant(s) and a diaryl carbonate ester, such as diphenylcarbonate, in the presence of a transesterification catalyst in aBANBURY® mixer, twin screw extruder, or the like to form a uniformdispersion. Volatile monohydric phenol is removed from the moltenreactants by distillation and the polymer is isolated as a moltenresidue. A specifically useful melt process for making polycarbonatesuses a diaryl carbonate ester having electron-withdrawing substituentson the aryls. Examples of diaryl carbonate esters with electronwithdrawing substituents include bis(4-nitrophenyl)carbonate,bis(2-chlorophenyl)carbonate, bis(4-chlorophenyl)carbonate, bis(methylsalicyl)carbonate, bis(4-methylcarboxylphenyl)carbonate,bis(2-acetylphenyl)carboxylate, bis(4-acetylphenyl)carboxylate, or acombination comprising at least one of the foregoing. In addition,useful transesterification catalyst for use can include phase transfercatalysts of formula (R³)₄Q⁺X above, wherein each R³, Q, and X are asdefined above. Transesterification catalysts include tetrabutylammoniumhydroxide, methyltributylammonium hydroxide, tetrabutylammonium acetate,tetrabutylphosphonium hydroxide, tetrabutylphosphonium acetate,tetrabutylphosphonium phenolate, or a combination comprising at leastone of the foregoing.

Branched polycarbonate blocks can be prepared by adding a branchingagent during polymerization. These branching agents includepolyfunctional organic compounds containing at least three functionalgroups selected from hydroxyl, carboxyl, carboxylic anhydride,haloformyl, and mixtures of the foregoing functional groups. Specificexamples include trimellitic acid, trimellitic anhydride, trimellitictrichloride, tris-p-hydroxy phenyl ethane (THPE), isatin-bis-phenol,tris-phenol TC (1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene),tris-phenol PA (4(4(1,1-bis(p-hydroxyphenyl)-ethyl)alpha,alpha-dimethylbenzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid, andbenzophenone tetracarboxylic acid. The branching agents can be added ata level of 0.05 to 2.0 wt %. Mixtures comprising linear polycarbonatesand branched polycarbonates can be used.

Endcapping agents can be added to the polymerization reaction, providedthat such agents do not adversely affect the desired properties of thecompositions significantly, in particular low smoke density and low heatrelease, as well as properties such as transparency, ductility, flameretardance, and the like. Examples of endcapping agents included acyanophenol, specifically p-cyanophenol, and other mono-phenoliccompounds, mono-carboxylic acid chlorides, and/or mono-chloroformates.Mono-phenolic chain stoppers are exemplified by monocyclic phenols suchas phenol and C₁-C₂₂ alkyl-substituted phenols such as p-cumyl-phenol,resorcinol monobenzoate, and p- and tertiary-butyl phenol; andmonoethers of diphenols, such as p-methoxyphenol. Alkyl-substitutedphenols with branched chain alkyl substituents having 8 to 9 carbonatoms can be specifically mentioned. Certain mono-phenolic UV absorberscan also be used as a capping agent, for example4-substituted-2-hydroxybenzophenones and their derivatives, arylsalicylates, monoesters of diphenols such as resorcinol monobenzoate,2-(2-hydroxyaryl)-benzotriazoles and their derivatives,2-(2-hydroxyaryl)-1,3,5-triazines and their derivatives, and the like.Mono-carboxylic acid chlorides can also be used with cyanophenols aschain stopping agents. These include monocyclic, mono-carboxylic acidchlorides such as benzoyl chloride, C₁-C₂₂ alkyl-substituted benzoylchloride, toluoyl chloride, halogen-substituted benzoyl chloride,bromobenzoyl chloride, cinnamoyl chloride, 4-nadimidobenzoyl chloride,and combinations comprising at least one of the foregoing; polycyclic,mono-carboxylic acid chlorides such as trimellitic anhydride chloride,and naphthoyl chloride; and combinations of monocyclic and polycyclicmono-carboxylic acid chlorides. Chlorides of aliphatic monocarboxylicacids with less than or equal to 22 carbon atoms are useful.Functionalized chlorides of aliphatic monocarboxylic acids, such asacryloyl chloride and methacryoyl chloride, are also useful. Also usefulare mono-chloroformates including monocyclic, mono-chloroformates, suchas phenyl chloroformate, alkyl-substituted phenyl chloroformate, p-cumylphenyl chloroformate, toluene chloroformate, and combinations comprisingat least one of the foregoing.

In addition to the polycarbonates and TBBPA copolymer or brominatedoligomer, the polycarbonate compositions can include various additivesordinarily incorporated into flame retardant compositions of this type,with the proviso that the additive(s) are selected so as to notadversely affect the desired properties of the thermoplastic compositionsignificantly, in particular low heat release and low smoke density.Such additives can be mixed at a suitable time during the mixing of thecomponents for forming the composition. Exemplary additives includefillers, reinforcing agents, antioxidants, heat stabilizers, lightstabilizers, ultraviolet (UV) light stabilizers, plasticizers,lubricants, mold release agents, antistatic agents, colorants such assuch as titanium dioxide, carbon black, and organic dyes, surface effectadditives, radiation stabilizers, additional flame retardants, andanti-drip agents. A combination of additives can be used. In general,the additives are used in the amounts generally known to be effective.The total amount of additives (other than any filler or reinforcingagents) is generally 0.01 to 25 parts per parts per hundred parts byweight of the combination of the first polymer, second TBBPA copolymer,and optional one or more third polymers, or the combination of the firstpolymer, the brominated oligomer, and the additional polycarbonate(PHR).

In an advantageous embodiment, it has been found that certain importantadditives can be used without adversely affecting the heat release andlow smoke properties of the polycarbonate compositions significantly, inparticular UV stabilizers, heat stabilizers (including phosphites),other flame retardants (such as Rimar salts) and certain pigments. Theuse of pigments such as titanium dioxide produces white compositions,which are commercially desirable. Pigments such as titanium dioxide (orother mineral fillers) can be present in the polycarbonate compositionsin amounts of 0 to 12 PHR, 0.1 to 9 PHR, 0.5 to 5 PHR, or 0.5 to 3 PHR,each based on the total weight of the first polycarbonate, second TBBPAcopolymer, and optional third polycarbonate, or based on the totalweight of the first polycarbonate, the brominated oligomer, and theadditional polycarbonate.

Exemplary antioxidant additives include organophosphites such astris(nonyl phenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite,bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearylpentaerythritol diphosphite; alkylated monophenols or polyphenols;alkylated reaction products of polyphenols with dienes, such astetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnamate)]methane;butylated reaction products of para-cresol or dicyclopentadiene;alkylated hydroquinones; hydroxylated thiodiphenyl ethers;alkylidene-bisphenols; benzyl compounds; esters ofbeta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid with monohydricor polyhydric alcohols; esters ofbeta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid withmonohydric or polyhydric alcohols; esters of thioalkyl or thioarylcompounds such as distearylthiopropionate, dilaurylthiopropionate,ditridecylthiodipropionate,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate;amides of beta-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, orcombinations comprising at least one of the foregoing antioxidants.Antioxidants are used in amounts of 0.01 to 0.1 parts by weight, basedon 100 parts by weight of the total composition, excluding any filler.

Exemplary heat stabilizer additives include organophosphites such astriphenyl phosphite, tris-(2,6-dimethylphenyl)phosphite, tris-(mixedmono- and di-nonylphenyl)phosphite; phosphonates such as dimethylbenzenephosphonate, phosphates such as trimethyl phosphate, or combinationscomprising at least one of the foregoing heat stabilizers. Heatstabilizers are used in amounts of 0.01 to 0.1 PHR.

Light stabilizers and/or ultraviolet light (UV) absorbing additives canalso be used. Exemplary light stabilizer additives includebenzotriazoles such as 2-(2-hydroxy-5-methylphenyl)benzotriazole,2-(2-hydroxy-5-tert-octylphenyl)-benzotriazole and 2-hydroxy-4-n-octoxybenzophenone, or combinations comprising at least one of the foregoinglight stabilizers. Light stabilizers are used in amounts of 0.01 to 5PHR.

Exemplary UV absorbing additives include hydroxybenzophenones;hydroxybenzotriazoles; hydroxybenzotriazines; cyanoacrylates;oxanilides; benzoxazinones;2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol (CYASORB®5411); 2-hydroxy-4-n-octyloxybenzophenone (CYASORB® 531);2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)-phenol(CYASORB® 1164); 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one)(CYASORB® UV-3638);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane(UVINUL® 3030); 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one);1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane;nano-size inorganic materials such as titanium oxide, cerium oxide, andzinc oxide, all with particle size less than or equal to 100 nanometers;or combinations comprising at least one of the foregoing UV absorbers.UV absorbers are used in amounts of 0.01 to 5 PHR.

Plasticizers, lubricants, and/or mold release agents can also be used.There is considerable overlap among these types of materials, whichinclude phthalic acid esters such asdioctyl-4,5-epoxy-hexahydrophthalate;tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- orpolyfunctional aromatic phosphates such as resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl)phosphate of hydroquinone and thebis(diphenyl)phosphate of bisphenol A; poly-alpha-olefins; epoxidizedsoybean oil; silicones, including silicone oils; esters, for example,fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate,stearyl stearate, pentaerythritol tetrastearate, and the like;combinations of methyl stearate and hydrophilic and hydrophobic nonionicsurfactants comprising polyethylene glycol polymers, polypropyleneglycol polymers, poly(ethylene glycol-co-propylene glycol) copolymers,or a combination comprising at least one of the foregoing glycolpolymers, e.g., methyl stearate and polyethylene-polypropylene glycolcopolymer in a solvent; waxes such as beeswax, montan wax, and paraffinwax. Such materials are used in amounts of 0.1 to 1 PHR.

Additional monomeric flame retardants include organic compounds thatinclude phosphorus, bromine, and/or chlorine. Non-brominated andnon-chlorinated phosphorus-containing flame retardants can be added forcertain applications, for example organic compounds containingphosphorus-nitrogen bonds.

Inorganic flame retardants can also be used, for example salts of C₁₋₁₆alkyl sulfonate salts such as potassium perfluorobutane sulfonate (Rimarsalt), potassium perfluorooctane sulfonate, tetraethylammoniumperfluorohexane sulfonate, and potassium diphenylsulfone sulfonate;salts such as Na₂CO₃, K₂CO₃, MgCO₃, CaCO₃, and BaCO₃, or fluoro-anioncomplexes such as Li₃AlF₆, BaSiF₆, KBF₄, K₃AlF₆, KAlF₄, K₂SiF₆, and/orNa₃AlF₆. When present, inorganic flame retardant salts are present inamounts of 0.01 to 10 parts by weight, more specifically 0.02 to 1 PHR.

Anti-drip agents in most embodiments are not used in the polycarbonatecompositions. Anti-drip agents include a fibril-forming or non-fibrilforming fluoropolymer such as polytetrafluoroethylene (PTFE). Theanti-drip agent can be encapsulated by a rigid copolymer, for examplestyrene-acrylonitrile copolymer (SAN). PTFE encapsulated in SAN is knownas TSAN. Antidrip agents are substantially absent or completely absentfrom the polycarbonate compositions in some embodiments.

Methods for forming the polycarbonate composition can vary. In anembodiment, the polycarbonates and brominated oligomer (if used) arecombined (e.g., blended) with any additives (e.g., a mold release agent)such as in a screw-type extruder. The polycarbonates, brominatedoligomer, and any additives can be combined in any order, and in form,for example, powder, granular, filamentous, as a masterbatch, and thelike. The composition can then be foamed, extruded into a sheet oroptionally pelletized. Methods of foaming a thermoplastic compositionusing frothing or physical or chemical blowing agents are known and canbe used. The pellets can be used for foaming, molding into articles, orthey can be used in forming a sheet of the flame retardant polycarbonatecomposition. In some embodiments, the composition can be extruded (orco-extruded with a coating or other layer) in the form of a sheet and/orcan be processed through calendaring rolls to form the desired sheet.

As discussed above, the polycarbonate compositions are formulated tomeet strict flammability requirements. The compositions have an E662smoke test D_(max) value of less than 200 when tested at a thickness of1.6 mm, and in some embodiments can further have a value of less than150, less than 100, less than 80, or 70 to 72. The polycarbonatecompositions can have an E662 smoke test D_(max) value of 70 to 200, 70to 150, 70 to 100, or 70 to 80.

The polycarbonate compositions can further have an OSU integrated 2minute heat release test value of less than 65 kW-min/m² and a peak heatrelease rate of less than 65 kW/m² as measured using the method of FARF25.4, in accordance with Federal Aviation Regulation FAR 25.853 (d). Insome embodiments the polycarbonate compositions can have an OSUintegrated 2 minute heat release test value of less than 55 kW-min/m²and a peak heat release rate of less than 55 kW/m² as measured using themethod of FAR F25.4, in accordance with Federal Aviation Regulation FAR25.853 (d).

The poly(siloxane) copolymer compositions, for example thepoly(siloxane-etherimide) copolymer compositions, can further beformulated to have a hydrogen to carbon ratio of 0.81:1 to 0.88:1.

The polycarbonate compositions can further have excellent impactstrength, particularly when the average value of E is higher, i.e., 25to 200, 25 to 100, or 25 to 50. Such compositions often have highersiloxane levels, i.e., at least 2.0 wt %, specifically 2.0 to 8 wt %,2.0 to 5 wt %, 2.0 to 4 wt %, or 2.0 to 3.5 wt %, each based on thetotal weight of the first polycarbonate, secondpoly(siloxane-carbonate), and optional third polycarbonate, or based onthe total weight of the first polycarbonate, the brominated oligomer,and the optional additional polycarbonate. An article molded from thepolycarbonate compositions can have a notched Izod impact of greaterthan 500 J/m as measured according to ASTM D 256-10 at a 0.125 inch (3.2mm) thickness. In some embodiments the articles have 80% or 100%ductility.

In some applications, it can be desirable to have a transparent article.Haze values, as measured using the color space CIE1931 (Illuminant C anda 2° observer), or by ANSI/ASTM D1003 (2007), Procedure A, illuminant C,can be a useful determination of the optical properties of thetransparent flame retardant polycarbonate sheet. The lower the hazelevels, the better the transparency of the finished sheet. Thepolycarbonate compositions can be formulated such that an article moldedfrom the composition has a haze less of than 15% and a transmission ofgreater than 75%, each measured using the color space CIE1931(Illuminant C and a 2° observer) or according to ASTM D 1003 (2007)using illuminant C at a 0.125 inch (3.2 mm) thickness. In someembodiments, the polycarbonate compositions can be formulated such thatan article molded from the composition has all three of a haze less ofthan 15% and a transmission of greater than 75%, each measured using thecolor space CIE1931 (Illuminant C and a 2° observer) or according toASTM D 1003 (2007) using illuminant C at a 0.125 inch (3.2 mm)thickness, and a room temperature notched Izod impact of greater than500 J/m as measured according to ASTM D 256-10 at a 0.125 inch (3.2 mm)thickness.

In an embodiment, haze levels for an article comprising thepolycarbonate composition, when measured at a thickness of 1.5millimeters (mm), can be less than 10%, specifically 0 to 10%, 0.5 to10%, and more specifically 1 to 10%, and transparency can be 70% orgreater, specifically 80% or greater, greater than or equal to 75%, morespecifically, greater than or equal to 90%, as measured using the colorspace CIE1931 (Illuminant C and a 2° observer), or in accordance withASTM D1003-07, Procedure A, illuminant C. These values can be obtainedeven when average value of E in the poly(siloxane-carbonate) is higher,i.e., 25 to 200, 25 to 100, or 25 to 50. Such compositions often havehigher siloxane levels, i.e., at least 2.0 wt %, specifically 2.0 to 8wt %, 2.0 to 5 wt %, 2.0 to 4 wt %, or 2.0 to 3.5 wt %, based on thetotal weight of the polymers (and oligomers, if present) in thepolycarbonate compositions. The TBBPA copolymer can be present in anamount from 35 to 50 wt %, and the bromine can be present in an amountof at least 7.8 wt %, specifically 8 to 25 wt %, more specifically 8 to13 wt %, or 10 to 13 wt %, each based on the total weight of the firstpolycarbonate, TBBPA copolymer, and optional third polycarbonate. Thebromine-containing oligomer can be present in an amount from 15 to 30 wt%, and the bromine can be present in an amount greater than 8 wt %,specifically 8 to 25 wt %, more specifically 8 to 13 wt %, based on thetotal weight of the first polycarbonate, the brominated oligomer, andthe additional.

In another embodiment, even greater transparency can be obtained whenthe first polycarbonate is a poly(siloxane-carbonate) copolymer havingaverage value of E that is lower, i.e., 5 to 75, 5 to 50, or 5 to 15,specifically 7 to 13, or 8 to 12. Such compositions further have atleast 30 wt %, specifically 30 to 80 wt %, or 30 to 60 wt % of the firstpolycarbonate, at least 20 wt %, specifically 20 to 70 wt %, or 20 to 65wt % of the TBBPA copolymer, and 0 to 50 wt %, specifically 0 to 30 wt%, or 5 to 20 wt % of the optional third copolymer; lower siloxanelevels, i.e., at least 0.3 wt %, specifically 0.3 to 2 wt %, 0.3 to 1 wt%, 0.3 to 0.8 wt %; and at least 5 wt %, specifically 5 to 20 wt %bromine, 5 to 10 wt %, or 7.8 to 13 wt % of bromine, each based on thetotal weight of the first polycarbonate, TBBPA copolymer, and optionalthird polycarbonate.

Density is a critical factor in aircraft components, and thepolycarbonate compositions can be formulated to have lower densities, inparticular a density of 1.31 g/cc or less, or 1.30 g/cc or less. Suchdensities can generally be obtained when the amount of bromine is lessthan 15 wt %, 13 wt %, 12 wt %, 11 wt %, 10 wt %, 9 wt %, 8 wt %, or 7.8wt %, each based on the total weight of the first polycarbonate, secondTBBPA copolymer, and optional third polycarbonate, or based on the totalweight of the first polycarbonate, the brominated oligomer, and theadditional polycarbonate of this embodiment.

The compositions can further have good melt viscosities, which aidsprocessing. The polycarbonate compositions can have a melt volume flowrate (MVR, cubic centimeter per 10 minutes (cc/10 min), according toASTM D 1238)) of less than 20, less than 19, less than 18, less than 17,less than 16, less than 15, or less than 12, measured at 300° C./1.2 Kgat 360 second dwell.

As mentioned throughout, the polycarbonate compositions can be used in awide variety of applications, particularly those requiring low smoke andlow heat release values. Articles comprising the polycarbonateapplications can be manufactured by foaming, molding, thermoforming,extruding, or casting the polycarbonate compositions. The polycarbonatecompositions can be used to form a foamed article, a molded article, athermoformed article, an extruded film, an extruded sheet, one or morelayers of a multi-layer article, a substrate for a coated article, or asubstrate for a metallized article.

Illustrative articles include access panels, access doors, air flowregulators air gaspers, air grilles, arm rests, baggage storage doors,balcony components, cabinet walls, ceiling panels, door pulls, doorhandles, duct housing, enclosures for electronic devices, equipmenthousings, equipment panels, floor panels, food carts, food trays, galleysurfaces, grilles, handles, housings for TVs and displays, light panels,magazine racks, telephone housings, partitions, parts for trolley carts,seat backs, seat components, railing components, seat housings, shelves,side walls, speaker housings, storage compartments, storage housings,toilet seats, tray tables, trays, trim panel, window moldings, windowslides, windows, and the like. The polycarbonate compositions areparticularly useful in train and aircraft, for example a variety ofaircraft compartment interior applications, as well as interiorapplications for other modes of transportation, such as bus, train,subway, marine, and the like. The articles manufactured from thecompositions described herein can thus be a component of an aircraft,train, marine, subway vehicle, or other transportation applications. Ina specific embodiment the articles interior components for aircraft ortrains, including access panels, access doors, air flow regulatorsbaggage storage doors, display panels, display units, door handles, doorpulls, enclosures for electronic devices, food carts, food trays,grilles, handles, magazine racks, seat components, partitions,refrigerator doors, seat backs, side walls, tray tables, trim panels,and the like. The polycarbonate compositions can be formed (e.g.,molded) into sheets that can be used for any of the above mentionedcomponents. It is generally noted that the overall size, shape,thickness, optical properties, and the like of the polycarbonate sheetcan vary depending upon the desired application.

In some applications, it can be desirable to have a transparent flameretardant article, such as a sheet. With regard to the transparency ofthe polycarbonate sheet, end user specifications (e.g., commercialairline specifications) generally specify that the component satisfy aparticular predetermined threshold. Haze values, as measured using thecolor space CIE1931 (Illuminant C and a 2° observer), or by ANSI/ASTMD1003-00, Procedure A, illuminant C, can be a useful determination ofthe optical properties of the transparent flame retardant polycarbonatearticles such as a sheet. The lower the haze levels, the better thetransparency of the finished article.

The transparent polycarbonate compositions have special utility inapplications requiring clarity, for example any of the above articles orcomponents can be manufactured using the transparent polycarbonatecompositions disclosed herein. In an embodiment, the transparentpolycarbonate compositions are used for the manufacture of balconycomponents, balusters for stairs and balconies, ceiling panels, coversfor life vests, covers for storage bins, dust covers for windows, layersof an electrochromic device, lenses for televisions, electronicdisplays, gauges, or instrument panels, light covers, light diffusers,light tubes and light pipes, mirrors, partitions, railings, refrigeratordoors, shower doors, sink bowls, trolley cart containers, trolley cartside panels, windows, or the like, particularly in aircraft, marinetransports, or trains.

Any of the foregoing articles, but in particular the transparentarticles, can further have a hardcoat disposed on a surface of thearticle to enhance abrasion and scratch resistance, chemical resistance,and the like. Hardcoats are known in the art, and include, for example,various polyacrylates such as hyperbranched polyacrylates, silicones,polyfluoroacrylates, urethane-acrylates, phenolics, perfluorpolyethers,and the like.

The disclosure is further illustrated by the following Examples. Itshould be understood that the non-limiting examples are merely given forthe purpose of illustration. Unless otherwise indicated, all parts andpercentages are by weight based upon the total weight of thepolycarbonates, or the total weight of the polycarbonates and brominatedoligomer in the polycarbonate compositions. The amount of additives isthus given in parts by weight per hundred parts by weight of the resins(PHR).

EXAMPLES Materials

The descriptions of the polycarbonates and polycarbonate copolymers usedin the Examples are described in Table 1. Methods for preparing thebrominated polycarbonates and the poly(siloxane-carbonate) copolymersare described after Table 1.

In Table 1, a reference to D10, D30, or D45 means a dimethylsiloxaneblock having an average length of 10.5+/−2.5, with two additionalterminal silicon group (with silicon hydride levels of less than 20 ppm,volatiles of less than 0.4%), 30+/−4 with two additional terminalsilicon groups (with silicon hydride levels of less than 20 ppm,volatiles of less than 0.4%, and D3 and D4 levels of less than 10 and1000 ppm respectively), or 45+/−5 with two additional terminal silicongroups (with silicon hydride levels of less than 20 ppm, volatiles ofless than 0.4%, and D3 and D4 levels of less than 10 and 1000 ppmrespectively). The values of D and wt % siloxane for the copolymers inTable 1 were as charged to the reactor.

The weight average molecular weights (Mw) of the polymers and copolymersin Table 1 were measured by gel permeation chromatography usingpolycarbonate standards. The endcap was PCP (p-cumyl phenol) or phenol.The percent of siloxane and bromine is weight percent based on theweight of the copolymer.

TABLE 1 Wt % Avg. Siloxane Wt % Acronym Description Mw PDI EndcapSiloxane Length Br TBBPA-BPA TetrabromoBPA/BPA Copolymer 23,660 2.6 PCP— — 26 BC52 Tetrabromo BPA Oligomer 2,638 1.7 Phenol — — 52 SiPC 1 D10siloxane block co-polycarbonate 30,000 — PCP 1 10 — SiPC 1B D10 siloxaneblock co-polycarbonate 22,200 — PCP 1 10 — SiPC 2 D10 siloxane blockco-polycarbonate 23,600 3.0 PCP 5 10 — SiPC 3 D30 siloxane blockco-polycarbonate 23,472 2.2 PCP 6 30 — SiPC 4 D45 siloxane blockco-polycarbonate 23,013 2.2 PCP 6 45 — SiPC 5 D45 siloxane blockco-polycarbonate 29,852 2.6 PCP 20  45 — PC 1 PCP Capped BPAPolycarbonate 21,900 2.5 PCP — — — PC 2 PCP Capped BPA Polycarbonate29,830 2.5 PCP — — —TBBPA-BPA Copolymer.

A representative reaction description for a 26 wt % brominecopolycarbonate batch is as follows.

To the formulation tank was added dichloromethane (16 L), DI water (12L), bisphenol-A (2250 g, 9.9 moles), tetrabromobisphenol-A (2250 g, 4.1moles), p-cumylphenol (102 g, 0.48 mole), triethylamine (75 g, 0.74mole) and sodium gluconate (10 g). The mixture was transferred to thebatch reactor. The reactor agitator was started and circulation flow wasset at 80 L/min. Phosgene flow to the reactor was initiated (80 g/minrate). A pH target of 10.0 was maintained throughout the batch by theaddition of 33% aqueous sodium hydroxide. The total phosgene additionamount was 2500 g (25.3 moles). After the phosgene addition wascomplete, a sample from the reactor was obtained and verified to besubstantially free of unreacted monomers and chloroformates. Mw of thereaction sample was determined by GPC (Mw=23660, PDI=2.6). The reactorwas purged with nitrogen then the batch was transferred to thecentrifuge feed tank. To the batch in the feed tank was added dilutiondichloromethane (10 L) then the mixture was purified using a train ofliquid-liquid centrifuges. Centrifuge one removed the brine phase.Centrifuge two removed the catalyst by extracting the polymer solutionwith aqueous hydrochloric acid (pH 1). Centrifuges three through eightsubstantially removed residual ions by extracting the polymer solutionwith DI water. A sample of the polymer solution was tested and verifiedless than 5 ppm each of ionic chloride and residual triethylamine.

The polymer solution was transferred to the precipitation feed tank. Thepolymer was isolated as a white powder by steam precipitation followedby drying in a cone shaped dryer using heated nitrogen (210° F.).Mw=23532. A pressed film of a sample of the polymer was transparent andtough.

SiPC 1 (1D10 Copolymer): A representative reaction description for a 1%siloxane D10 poly(siloxane-carbonate) is as follows. To the formulationtank was added dichloromethane (15 L), DI water (12 L), bisphenol-A(4410 g, 19.3 moles), D10 eugenol-capped siloxane (90 g, 0.07 moles),p-cumylphenol (174 g, 0.82 mole), triethylamine (30 g, 0.30 mole) andsodium gluconate (10 g). The mixture was transferred to the batchreactor. The reactor agitator was started and circulation flow was setat 80 L/min Phosgene flow to the reactor was initiated (80 g/min rate).A pH target of 10.0 was maintained throughout the batch by the additionof 33% aqueous sodium hydroxide. The total phosgene addition amount was2300 g (23.3 moles). After the phosgene addition was complete, a samplefrom the reactor was obtained and verified to be substantially free ofunreacted BPA and chloroformates. Mw of the reaction sample wasdetermined by GPC (Mw=22370 Daltons, PDI=2.4). The reactor was purgedwith nitrogen then the batch was transferred to the centrifuge feedtank.

To the batch in the feed tank was added dilution dichloromethane (10 L)then the mixture was purified using a train of liquid-liquidcentrifuges. Centrifuge one removed the brine phase. Centrifuge tworemoved the catalyst by extracting the polymer solution with aqueoushydrochloric acid (pH 1). Centrifuges three through eight substantiallyremoved residual ions by extracting the polymer solution with DI water.A sample of the polymer solution was tested and verified less than 5 ppmeach of ionic chloride and residual triethylamine.

The polymer solution was transferred to the precipitation feed tank. Thepolymer was isolated as a white powder by steam precipitation followedby drying in a cone shaped dryer using heated nitrogen (99° C. (210°F.)).

SiPC 2 (5D10 Copolymer).

A representative reaction description for a 5 wt % siloxane D10poly(siloxane-carbonate) batch is as follows.

To the formulation tank was added dichloromethane (15 L), DI water (12L), bisphenol-A (4125 g, 18.1 moles), D10 eugenol capped siloxane (375g, 0.30 moles), p-cumylphenol (166 g, 0.78 mole), triethylamine (30 g,0.30 mole) and sodium gluconate (10 g). The mixture was transferred tothe batch reactor. The reactor agitator was started and circulation flowwas set at 80 L/min. Phosgene flow to the reactor was initiated (80g/min rate). A pH target of 10.0 was maintained throughout the batch bythe addition of 33% aqueous sodium hydroxide. The total phosgeneaddition amount was 2300 g (23.3 moles). After the phosgene addition wascomplete, a sample of the reactor was obtained and verified to besubstantially free of unreacted BPA and chloroformates. Mw of thereaction sample was determined by GPC (Mw=21991 Daltons, PDI=2.6). Thereactor was purged with nitrogen then the batch was transferred to thecentrifuge feed tank.

To the batch in the feed tank was added dilution dichloromethane (10 L)then the mixture was purified using a train of liquid-liquidcentrifuges. Centrifuge one removed the brine phase. Centrifuge tworemoved the catalyst by extracting the polymer solution with aqueoushydrochloric acid (pH 1). Centrifuges three through eight substantiallyremoved residual ions by extracting the polymer solution with DI water.A sample of the polymer solution was tested and verified less than 5 ppmeach of ionic chloride and residual triethylamine.

The polymer solution was transferred to the precipitation feed tank. Thepolymer was isolated as a white powder by steam precipitation followedby drying in a cone shaped dryer using heated nitrogen (210° F.).Mw=21589 Daltons.

SiPC 3 (6D30 Copolymer).

The 6D30 copolymer (6 wt % siloxane D30 poly(siloxane-carbonate)) wasmade in similar fashion to Examples 14 and 15 in U.S. Pat. No. 6,870,013using a D30 eugenol-capped siloxane fluid. The polymer contains about 6wt % siloxane. The Mw is about 23,500 Daltons.

SiPC 4 (6D45 Copolymer).

The 6D45 polymer (6 wt % siloxane D45 poly(siloxane-carbonate)) was madein similar fashion to Examples 14 and 15 in U.S. Pat. No. 6,870,013using D45 eugenol-capped siloxane fluid. The polymer contains about 6%siloxane. The Mw is about 23,000 Daltons.

SiPC 5 (20D45 Copolymer):

The 20D45 polymer (20 wt % siloxane D45 poly(siloxane-carbonate)) wasmade in a like manner to the 5D10 poly(siloxane-carbonate) except that aD45 eugenol-capped siloxane fluid was used. The polymer contains about20% siloxane. The Mw is about 30,000 Daltons.

The additive types and details that were used in the compositions of theExamples are shown in Table 2.

TABLE 2 Component Chemical Name Supplier Grade Phosphite Tris(2,4-di-tert-butylphenyl) phosphite various DF1040 Methylhydrogensiloxane fluid Momentive Performance DF 1040 Materials OPTSOctaphenylcyclotetrasiloxane Shin-Etsu Chemical — Company D4Octamethyltetrasiloxane Aldrich Chemical — Company KSS Potassiumdiphenylsulfone sulfonato Arichem LLC KSS Rimar salt Potassiumperfluorobutane sulfonato Lanxess Bayowet C4 STB Sodium trichlorobenzenesulfonato Arichem LLC STB sesquihydrate TSAN SAN encapsulated PTFE SabicInnovative Plastics TSAN TiO₂ Type 1 Titanium dioxide, (organic coating)Kronos Kronos 2233 TiO₂ Type 2 Titanium dioxide, (organic coating)Kronos KRONOS 2450 Phosphorus acid Phosphorus acid solution (0.15%)Tinuvin 1577 2-(4,6-Diphenyl-1,3,5-triazin-2-yl)-5- Ciba SpecialtyCompany Tinuvin 1577 FF hexyloxyphenol Corp. UVA 2342-(2-hydroxy-3,5-di-cumyl)benzotriazole Ciba Specialty Company Tinuvin234 Corp. Cyasorb 3638 4H-3, 1-benzoxazin-4-one,2,2′-(1,4- CYTECIndustries CYASORB UV- phenylene)bis- 3638Extrusion and Molding Conditions.

Extrusions were performed either on a single screw extruder or atwin-screw extruder. Typically, the D10poly(siloxane-carbonate)-containing compositions and correspondingcontrols were performed on a single or a twin screw extruder. The D30and D40 poly(siloxane-carbonate)-containing compositions andcorresponding controls were performed on a twin screw extruder.

The compositions prepared with a single screw extruder were made asfollows. All ingredients were dry blended for about 4 minutes using apaint shaker. The single screw extruder was a Sterling 1¾ inch (44.5 mm)extruder (Length/Diameter (L/D) ratio=24/1, with a vacuum port locatednear die face, with barrel and die temperature set points of 270, 275,288, 288° C.).

The compositions prepared on the 30 mm WP twin screw extruder were madeas follows. All ingredients were dry blended for about 4 minutes using apaint shaker or a drum tumbler. The twin screw extruder contained avacuum port located near die face. Typically, the compositions werecompounded with an applied vacuum of 20+ inches of Hg.

The compositions prepared on a W&P 50 mm Mega twin screw were made asfollows. All additives (stabilizers and/or colorants) were dry blendedoff-line as concentrates using one of the primary polymer powders as acarrier and starve-fed via gravimetric feeder(s) into the feed throat ofthe extruder. The remaining polymer(s) were starve-fed via gravimetricfeeder(s) into the feed throat of the extruder as well. The compositionswere compounded with an applied vacuum of 20+ inches of Hg. The extruderwas a nine-barrel machine (approx. Length/Diameter (L/D) ratio=36:1)with a vacuum port located in barrel 7.

The compositions were molded after drying at 121° C. for 4 hrs on a260-ton (236 metric ton) Van Dorn or an 85 Ton Van Dorn molding machineoperating at about 300 to 320° C. with a mold temperature of about 80°C. It will be recognized by one skilled in the art that the method isnot limited to these temperatures or processing equipment.

Testing Methods.

Standard ASTM testing was performed at 50% relative humidity (RH) andunless otherwise indicated at room temperature (RT).

Notched Izod (NI-125) testing was conducted according to ASTM D 256-10on a molded sample having a 0.125 inch (3.2 mm) thickness.

Multiaxial impact (MAI) was measured at a speed of 3.3 m/s on a 3.2×102mm disc using a plunger with a hemispherical end and a diameter 12.70 mmin accordance with ASTM D3763

Heat deflection temperature was measured on an annealed 3.2 mm sample inaccordance with ASTM D 648 using a stress of 0.455 or 1.82 Mpa.

The tensile properties were measured in accordance with ASTM D638 at 50mm/min.

The flexural properties were measured in accordance with ASTM D 790 at1.27 mm/min.

In most cases, melt volume ratio (MVR) was run at 300° C./1.2 Kg at 360second dwell.

Molecular weight was measured via GPC using polycarbonate standards.

The reported transmission data (% T) was measured at the indicatedthickness on a Gretagmacbeth Color-Eye 7000A (Propalette Optiview Goldversion 5.2.1.7) using the color space CIE1931 (Illuminant C and a 2°observer) and is equivalent to the “Y” tristimulus value.

The reported the yellowness Index (YI) data was measured at theindicated thickness on a Gretagmacbeth Color-Eye 7000A (PropaletteOptiview Gold version 5.2.1.7) in accordance with ASTM E313-73 (D1925)using Illuminant C and a 2° observer.

Heat release testing was performed on 15.2×15.2 cm plaques 1.5 mm thickusing the Ohio State University (OSU) rate-of-heat release apparatus, inaccordance with the method shown in FAR 25.853 (d), and in Appendix F,section IV (FAR F25.4). Total heat release was measured at thetwo-minute mark in kW-min/m² (kilowatt minutes per square meter). Peakheat release was measured as kW/m² (kilowatts per square meter). Theheat release test method is also described in the “Aircraft MaterialsFire Test Handbook” DOT/FAA/AR-00/12, Chapter 5 “Heat Release Test forCabin Materials.”

Smoke density testing (ASTM E-662-83, ASTM F-814-83, Airbus ABD0031,Boeing BSS 7239) was performed on 7.5×7.5 cm plaques of 1.5 mm thicknessaccording to the method shown in FAR 25.853 (d), and in Appendix F,section V (FAR F25.5). Smoke density was measured under flaming mode.Smoke density (D_(s)) at 4.0 min, and the max level (DsMax) werereported.

Low Heat Release and Low Smoke Density Compositions.

1. 1D10 (SiPC 1) Blends with TBBPA-BPA Copolymer.

Table 3 illustrates that a combination of a poly(siloxane-carbonate)having an average siloxane block length (D) of about 10 units and 1 wt %siloxane in the copolymer and a bromine-containing copolycarbonate canproduce a blend composition with excellent flame and smoke performance(EX 1-4) compared with compositions having only the brominatedcopolycarbonate (CEX 2-6), only the poly(siloxane-carbonate) (CEX 1) oronly a polycarbonate without either the poly(siloxane-carbonate) or thebrominated polycarbonate present (CEX 2).

Specifically a composition having poly(siloxane-carbonate) incombination with a polycarbonate (CEX 1) passes the smoke testing(DsMax) target of less than 200 with a value of 109 but fails the2-minute OSU test target of less than 65 kW-min/m² with a value of 68and also fails the peak OSU test target of less than 65 with a value of98. As brominated copolycarbonate is added to the composition the2-minute OSU performance and the peak OSU performance improves (EX 1-EX4) and both the target values for the 2-minute and peak OSU targetvalues are achieved (values below 65) while the smoke performance(DsMax) is maintained at passing levels (values less than 200). Thisimprovement in flame test performance was achieved with as little as 5.2wt % bromine in the composition (EX 1). In addition, EX 1-EX 4 all havedensities below the targeted maximum density of 1.320 for aircraftapplications. A polycarbonate composition without thepoly(siloxane-carbonate) or the brominated copolycarbonate (CEX 2) alsofails both the 2-minute and peak OSU performance tests with values of 73and 139 although it too passes the smoke test (DsMax) with a value of139. The benefit of the presence of siloxane in the composition isillustrated by compositions that only contain the brominatedcopolycarbonate only (CEX 3-6). They pass the OSU flame testing with2-minute values of less than 65 and the OSU peak testing with values ofless than 65 but perform very poorly in the smoke test exceeding thetarget of less than 200 with values of 561, 382 and 467.

Furthermore, the clarity as measured by % transmission and % haze isexcellent for the poly(siloxane-carbonate) compositions with thebrominated copolycarbonate (EX 1-4) with transmission values of 88% orgreater and haze values of 1.2% or less. These values are as good orbetter than the polycarbonate control (CEX 2) with a transmission of 89and a % haze of 2.4. The yellowness index value, a measure of how

TABLE 3 Components and Properties CEX 1 EX 1 EX 2 EX 3 EX 4 CEX 2 CEX 3CEX 4 CEX 5 CEX 6 TBBPA-BPA 0 20 30 40 50 0 20 30 40 80 SiPC 1 40 40 4040 40 PC 2 60 40 30 20 10 100 80 70 60 50 IRGAPHOS 168 0.0 0.0 0.0 0.00.0 0.0 0.0 0.0 0.0 0.0 Formulated Total wt % Siloxane 0.4 0.4 0.4 0.40.4 0 0 0 0 0 Composition Total wt % Bromine 0 5.2 7.8 10.4 13 0 5.2 7.810.4 13 ~Siloxane D Length 10 10 10 10 10 — — — — — MVR 6.5 6.0 5.6 5.65.3 6.4 6.6 6.8 6.8 6.4 NI-125, RT Ductility 100 100 0 0 0 100 100 0 0 0J/m 949 867 128 109 92 887 850 130 91 87 Ft-lbs/in 17.8 16.2 2.4 2.0 1.716.6 15.9 2.4 1.7 1.6 MAI-RT Ductility 100.0 100.0 100.0 100.0 100.0100.0 100.0 100.0 100.0 100.0 Energy to max load-Avg J 79 78 76 75 81 7575 76 78 78 Energy to failure-Avg J 91 90 89 88 89 81 81 82 84 83Energy, Total-Avg J 91 90 89 88 89 81 81 84 84 83 Density-Avg g/cc 1.1941.239 1.268 1.288 1.314 1.198 1.242 1.265 1.289 1.315 SpecificGravity-Avg 1.197 1.242 1.271 1.291 1.317 1.198 1.243 1.266 1.290 1.316HDT-ASTM-GLB-MTV 1.8 MPa 128 132 137 137 142 132 137 139 142 143 OSUTest FAR25.853 (d) Appendix F, Part IV 2 Min OSU Average 68 35 30 25 1173 24 26 30 17 Standard deviation 14 7 1 4 10 19 4 5 3 2 Peak OSUAverage 98 63 54 48 43 139 70 57 66 56 Standard deviation 8 4 3 2 1 1411 5 8 14 NBS Smoke Density (ASTM F814/E662, Flaming Mode) DsMax Ave 109139 68 97 59 137 561 382 457 304 Standard deviation 28 44 32 18 23 19164 69 243 181 Optical Properties Optical % T at 62 mil (1.58 mm) 89 8989 88 88 89 89 89 88 88 Properties YI 2.7 2.7 2.9 5.1 5.2 2.4 3.3 4.15.0 5.0 % Haze 1.0 0.6 0.7 0.8 1.2 2.4 1.7 1.4 1.8 1.7yellow the part appears, for EX 1 and EX 2 at 2.7 and 2.9 is also veryclose to the value for the polycarbonate control 2.4. As the brominatedcopolycarbonate content increases the yellowness index increasessignificantly from 2.5 (EX 1) at 5.2% bromine content to 5.2 at 13%bromine content (EX 4). High clarity, low yellowness, and low densityvalues in combination with excellent flame and smoke performance arecritical for use of these compositions in airplane window applicationsand so higher bromine content compositions are expected to have limitedutility in window applications.

Notched Izod impact values at or near 2 ft-lbs/in (1.00 J/cm) or greatercan also provide sufficient ductility for preparation of polycarbonatesheet for use in window applications and EX 1-3 possess the targetedductility performance for window applications as well. As the brominecontents of the compositions increase the notched Izod ductilitydecreases to values less than 2 (EX 4 and CEX 5-6) and so high brominecontents in the compositions at 11% or greater would likely not beuseful in window applications.

2. 5D10 Compositions (SiPC 2) with TBBPA-BPA Copolymer

The results in Table 4 using a poly(siloxane-carbonate) having anaverage siloxane block length of 10 units and 5 wt % siloxane in thecopolycarbonate further illustrates that a combination of poly(siloxane)block copolycarbonates and a brominated copolycarbonate outperformseither poly(siloxane) block co polycarbonate compositions or thebrominated polycarbonate compositions in OSU flame and smoke densitytesting.

TABLE 4 Components and Properties CEX 7 EX 5 EX 6 EX 7 EX 8 CEX 8TBBPA-BPA 0 50 70 80 90 100 SiPC 2 100 50 30 20 10 0 IRGAPHOS 168 0.060.06 0.06 0.06 0.06 0.06 Formulated Total wt % Siloxane 5.0 2.5 1.5 1.00.5 0.0 Composition Total wt % Bromine 0.0 13.0 18.2 20.8 23.4 26.0~Siloxane D Length 10 10 10 10 10 10 MVR-6 min Cc/10 min. 18.4 10.1 7.97.6 5.6 4.6 Tg ° C. 141 161 168 170 178 182 NI-125 RT Ductility 100 0 00 0 0 J/m 721 127 78 68 57 50 ft-lbs/in 13.5 2.4 1.5 1.3 1.1 0.9 MAI-RTDuctility 100 100 100 100 100 60 Energy to max load-Avg J 65 66 76 76 7777 Energy to failure-Avg J 73 72 82 82 82 83 Energy, Total-Avg 73 72 8283 82 83 Modulus of Elasticity-Avg MPa 2220 2410 2500 2620 2660 Stressat Yield-Avg MPa 58 68 72 74 77 Stress at Break-Avg MPa 50 60 61 61 65Elongation at Yield-Avg % 6 7 7 7 7 Elongation at Break-Avg % 87 105 9592 102 Flexural Modulus-Avg MPa 2100 2280 2480 2420 2450 Flex Stress at5% Strain-Avg MPa 84 93 99 98 101 Flexural Stress atYield-Avg MPa 92 106114 113 118 Density-Avg g/cc 1.183 1.307 1.363 1.385 1.422 1.450Specific Gravity-Avg 1.186 1.310 1.367 1.388 1.426 1.454HDT-ASTM-GLB-MTV  1.8 MPa 117 134 136 146 150 156 HDT-ASTM-GLB-MTV 0.455MPa 130 147 154 159 165 171 OSU Test FAR25.853 (d) Appendix F, Part IVOSU 2 Min. Average 102 40 27 34 28 26 Standard deviation 11 3 6 3 6 5OSU Peak Average 93 45 37 36 37 47 Standard deviation 13 2 3 3 3 12 NBSSmoke Density (ASTM F814/E662, Flaming Mode) DsMax Ave 80.7 14.7 12.09.0 12.7 60.7 Standard deviation 33.6 0.6 4.4 2.6 2.1 20.5 OpticalProperties % T at 62 mil (1.58 mm) 88.6 85.8 86.0 86.5 88.2 89.0 YI 2.813.4 13.1 6.4 3.8 2.9 % Haze 12.2 5.5 4.1 2.4 0.9 1.1

CEX 7 contains no bromine and fails both the OSU 2 min total and peakheat release tests with values greater than 65. CEX 7 in this testpassed the D_(max) flame test. CEX 8 has no siloxane present and itpasses the OSU flame and peak heat release test with values below 65 butthe Dmax values while passing with a value below 200, However, CEX 8 isextremely brittle which would make it difficult to machine and form intoparts, and has a high density, which would by deleterious to weightsavings needed to manufacture fuel efficient aircraft. By contrast,compositions having poly(siloxane-carbonate) and brominatedcopolycarbonate passed OSU flame and peak heat test with values below 65and exhibited Dmax smoke results of less than 15 with standarddeviations below 4.4 units.

3. 6D30 (SiPC 2), 6D45 (SiPC 3) and 20D45 (SiPC 3) Compositions withTBBPA-BPA Copolymer

The flame and smoke performances of a series of compositions using abromine copolycarbonate having 26 wt % bromine atoms with siloxane blockco-polycarbonates having average siloxane chain lengths of 45 and 30 andsiloxane contents of 6 wt % in the copolymer and with apoly(siloxane-carbonate) having an average of 45 siloxane units and 20wt % siloxane in the copolymer are shown in Table 5.

Examples EX 9-22 illustrate that the OSU flame and heat performance aswell as smoke performance is maintained in compositions ofpoly(siloxane-carbonate)s and brominated polycarbonate copolymers withsiloxane change lengths of 30 and 45 siloxane units and siloxane wt % aslow as 5 wt % and as high as 20 wt % in the copolymers. Comparativeexample CEX 9 and CEX 5 (Table 3) that have no poly(siloxane-carbonate)in the compositions either fail the DsMax smoke test with a value of 195and 457 or inconsistently pass as a result of high values and a highstandard deviation of 78 and 243 units, respectively. This resultillustrates once again that the presence of siloxane in the blend isnecessary to achieve consistent smoke performance pass values.

EX 16 (without heat stabilizer), when compared with EX 17 (containsimilar siloxane and bromine content as EX 16 but with heat stabilizer),demonstrates that the heat stabilizer IRGAPHOS 168 has no significanteffect on the flame or smoke performance in the compositions.

High Impact Compositions.

Formulations passing both the OSU flame and smoke tests and havingexcellent room temperature ductility performance and high flowproperties can also be achieved by some of the combinations ofbrominated polycarbonate copolymers and poly(siloxane-carbonate)s. ForExample EX 9, 12 and 22 in Table 5 passed the 2-min flame and heatrelease tests with flame and heat release values less than 65 and smokevalues below 200 and showed excellent room temperature ductility with100% ductility and with impact energies of greater than 500 J/m at highmelt flow values (MVR values of 9.6-12 cc/10 min.). The results fromTable 5 shows that compositions with polysiloxane content greater than1% achieve high room temperature impact (both EX 14 and EX 15 haveidentical bromine content but EX 14 has 1% polysiloxane content while EX15 has 2 wt % polysiloxane content and EX 14 has no ductility and roomtemperature while EX 15 shows partial room temperature ductility).Furthermore it is also desirable for the compositions to have less than13 wt % brominated copolycarbonate content in order to achieve highductility (EX 9 and EX 10 both have 2 wt % polysiloxane in theircompositions but EX 9 has 10.4 wt % bromine content from the brominatedcopolymer while EX 10 has 13 wt % bromine content and EX 9 has excellentroom temperature impact while EX 10 has low room temperature impact).The examples show that the poly(siloxane-carbonate)s that have 20 wt %polysiloxane content are somewhat more efficient in providing highductility and room temperature impact strength than the copolymers with6 wt % content. EX 9 was made from a poly(siloxane-carbonate) having 20wt % polysiloxane in the copolymer and EX 15 was made from apoly(siloxane-carbonate) having 6 wt % polysiloxane in the copolymer,and both have identical bromine and polysiloxane contents, but EX 9 hasa higher impact and ductility value than EX 15.

TABLE 5 Components, Properties EX 9 EX 10 EX 11 EX 12 EX 13 EX 14 EX 15EX 16 TBBPA-BPA 40 50 60 30 40 40 40 40 20D45 SiPC 5 10 10 10 6D45 SiPC4 34 9 17 34 34 6D30 SiPC 3 PC1 50 40 30 36 51 43 26 26 PC 2 IRGAPHOS168 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.00 Total Wt % Siloxane 2.0 2.02.0 2.0 0.5 1.0 2.0 2.0 Formulation Wt % Bromine 10.4 13.0 15.6 7.8 10.410.4 10.4 10.4 Siloxane D Length 45 45 45 45 45 45 45 45 MVR-6 min Cc/10min. 11.1 9.7 7.5 13.6 15.8 13.7 11.4 11.4 Tg ° C. 160 162 168 156 160160 160 160 NI-125 RT Ductility 100 0 0 100 0 0 60 40 J/m 579.0 154.0136.0 646 105 122 371 304 ft-lbs/in 10.8 2.9 2.5 12.1 2.0 2.3 6.9 5.7MAI-RT Ductility 100 100 100 100 100 100 100 100 Energy to max load-AvgJ 71 74 76 75 73 77 75 75 Energy to failure-Avg J 75 77 81 82 77 82 8381 Energy, Total-Avg J 75 77 81 82 77 82 83 81 Density-Avg g/cc 1.2811.306 1.330 1.254 1.284 1.281 1.277 1.276 Specific Gravity-Avg 1.2841.309 1.333 1.257 1.287 1.284 1.280 1.279 HDT 1.8 MPa 139 141 144 128134 133 132 132 2 Min OSU Average 32 23 19 46 39 41 45 35 Std. dev. 3.21.9 4.7 5.7 3.6 6.0 4.5 2.7 Peak OSU Average 50 42 41 55 49 48 55 46Std. dev. 3.8 2.3 3.1 3.0 3.4 3.3 2.2 4.1 DsMax Ave 45 48 61 30 15 14 1829 Std. dev. 13 9 35 8 6 7 10 12 % T at 62 mil (1.58 mm) YI % Haze YI at125 mil (3.2 mm) 39 43 47 12 6 9 15 14 % T at 125 mil (3.2 mm) 29.6 27.324.1 83.1 86.7 84.8 80.8 81.6 % Haze at 125 mil (3.2 mm) 99.2 99.2 99.93.3 1.6 2.2 4.9 3.9 Components, Properties EX 17 EX 18 EX 19 EX 20 EX 21EX 22 CEX 9 TBBPA-BPA 40 50 60 70 50 40 40 20D45 SiPC 5 6D45 SiPC 4 3434 34 25 6D30 SiPC 3 42 50 PC1 26 16 6 PC 2 5 8 10 60 IRGAPHOS 168 0.060.06 0.060 0.060 0.06 0.06 0.06 Total Wt % Siloxane 2.0 2.0 2.0 1.5 2.53.0 0.0 Formulation Wt % Bromine 10.4 13.0 15.6 18.2 13.0 10.4 10.4Siloxane D Length 45 45 45 45 30 30 — MVR-6 min Cc/10 min. 10.5 9.0 7.06.0 7.3 7.7 15.4 Tg ° C. 159 163 167 171 164 161 158 NI-125 RT Ductility0 0 0 0 0 100 0 J/m 160.0 129.0 102.0 83.8 139 513.0 83.2 ft-lbs/in 3.02.4 1.9 1.6 2.6 9.6 1.6 MAI-RT Ductility 100 100 100 100 100 100 100Energy to max load-Avg J 73 73 71 73 58 72 69 Energy to failure-Avg J 7979 76 79 63 77 73 Energy, Total-Avg J 79 79 76 79 63 77 73 Density-Avgg/cc 1.281 1.307 1.329 1.360 1.305 1.277 1.291 Specific Gravity-Avg1.285 1.311 1.333 1.364 1.308 1.280 1.294 HDT 1.8 MPa 136 140 142 143136 131 139 2 Min OSU Average 27 23 20 34 32 40 28 Std. dev. 6.7 3.1 0.62.3 2 2 10.1 Peak OSU Average 47 45 42 38 33 42 54 Std. dev. 2.5 3.1 3.53.5 2 1 8.1 DsMax Ave 53 61 43 20 76 58 195 Std. dev. 22 10 12 4 55 1578 % T at 62 mil (1.58 mm) 75 79 87 YI 22.5 12.0 5.1 % Haze 14.6 12.16.6 YI at 125 mil (3.2 mm) 16 23 28 2 % T at 125 mil (3.2 mm) 79.9 72.963.9 89.3 % Haze at 125 mil (3.2 mm) 4.4 10.7 23.6 0.6In addition the data in Table 5 show that high impact values could beachieved using both the poly(siloxane-carbonate)s having averagesiloxane chain lengths of 45 and 30 repeating units. Furthermore, thehigh ductility can be achieved with copolymers having either 20%polysiloxane content or 6% polysiloxane content. In the case of thepoly(siloxane-carbonate)s that have 6% polysiloxane content, it is alsopossible to achieve transparency. One particular benefit of the use oflong siloxane chain lengths (chain lengths greater than 10 repeatingunits) and with about 6 wt % siloxane in the poly(siloxane-carbonate)copolymer is that a combination of high impact and transparency can beachieved in addition to maintaining excellent OSU flame and smokeperformance in the compositions. Specifically EX 12 with 2 wt % siloxaneand 7.8 wt % bromine content and that is formulated from apoly(siloxane-carbonate) having an average chain length of 45 siloxaneand about 6 wt % siloxane in the copolymer has 100% room temperatureductility during notched Izod testing, excellent haze with a value of3.3% and an excellent % transmission with of value of 88% while havingan OSU flame value of 46, a peak heat release value of 55 and a DsMaxsmoke value of 30. EX 22 with 3.0 wt % siloxane and 10.4 wt % brominethat is formulated from a poly(siloxane-carbonate) having an averagechain length of 30 siloxane units and about 6 wt % siloxane in thecopolymer also shows excellent impact performance, transparency, hazeand flame and smoke performance.Transparent Compositions.

Formulations that pass the OSU and smoke testing and that have very highpercent transmission values (greater than 85%), very low haze values(less than 2.5%) and low yellowness values (less than 6) are alsopossible to obtain using compositions of poly(siloxane-carbonate)s andbrominated polycarbonate copolymers. Formulations with hightransmission, low haze and low yellowness index values that pass OSUflame and smoke tests are particularly useful in window articles, gaugeand dashboard covers and in window dust covers on aircraft. Formulationsthat meet the OSU flame and smoke and requirements and that have highpercent transmissions, low haze and low yellowness index values can beobtained from a variety of poly(siloxane-carbonate)s with the brominatedpolycarbonate copolymer. Examples include EX 1, EX 2, EX 3 and EX 4 fromTable 3 above prepared from a poly(siloxane-carbonate) having 10polysiloxane repeating units and 1 wt % polysiloxane content in thecopolymer; EX 5, EX 6, EX 7, and EX 8 from Table 4 above prepared from apoly(siloxane-carbonate) have 10 polysiloxane repeating units and 5 wt %polysiloxane content in the copolymer; EX 13 and EX 14 from Table 5above prepared from a poly(siloxane-carbonate) have 45 polysiloxanerepeating units and 6 wt % polysiloxane content in the copolymer and EX22 from Table 5 above prepared from a poly(siloxane-carbonate) have 30polysiloxane repeating units and 6 wt % polysiloxane content in thecopolymer. The yellowness index generally increases as the wt % ofbrominated copolycarbonate in the compositions increases, the percenthaze generally increases as the wt % polysiloxane in the compositionincreases and the chain length of the polysiloxane increases (30 and 45polysiloxane chain lengths are worse than 10 polysiloxane chain lengths)and the % polysiloxane in the copolymer increases (20 wt % polysiloxanein the copolymer is much worse than 6 wt % polysiloxane) The resultsfurther suggest that the poly(siloxane-carbonate) providing the besttransparency, haze and YI values and yellowness index values for use inwindow applications is the poly(siloxane-carbonate) having approximately10 polysiloxane repeating units and 1 wt % polysiloxane content in thecopolymer.

Low OSU Heat Release, Low Smoke, TiO₂-Containing Compositions.

Titanium dioxide is a common additive used to increase the whiteness ofpolymer compositions. Compositions having poly(siloxane-carbonate) andbrominated copolycarbonate were prepared that also contained variousamounts of titanium dioxide in order to determine its effect on densityand stability of the polycarbonate compositions. The results are shownin Table 6.

TABLE 6 Blend Composition Components EX 23 EX 24 EX 25 EX 26 EX 27 EX 28EX 29 TBBPA-BPA 40.0 40.0 40.0 40.0 40.0 40.0 40.0 SiPC 4 50.00 50.0050.00 50.00 50.00 50.0 50.00 PC 1 10.0 10.0 10.00 10.00 10.00 10.0 10.0TiO₂ 0.0 1.0 2.0 3.0 4.0 5.0 7.0 IRGAPHOS 168 0.06 0.06 0.06 0.06 0.060.06 0.06 Total Total wt % Siloxane 3.00 3.00 3.0 3.00 3.00 3.00 3.00Formulation Total wt % Bromine 10.4 10.4 10.4 10.4 10.4 10.4 10.4 MVR-6min 8.2 8.7 8.86 8.69 8.44 8.52 8.46 MVR-18 min 8.8 9.3 9.73 9.73 9.9010.40 10.00 % MVR Change 6 min to 18 min 7.0 12.9 18.1 18.1 20.1 26.221.4 NI-125 RT Ductility 100 100 100 100 100 100 100 J/m 577 608 592 544515 520 487 ft-lbs/in 10.8 11.4 11.1 10.2 9.6 9.7 9.1 Density-Avg g/cc1.278 1.282 1.287 1.305 1.316 1.319 1.340 Specific Gravity-Avg 1.2811.286 1.290 1.308 1.319 1.322 1.343

The data in Table 6 illustrate that melt stability decreases as the TiO₂content increases (EX 24-EX 29) compared to a control that has no TiO₂present (EX 23) as measured by the change in the MVR values after 6 and18 minute heating at 300° C. To achieve 20% or less melt change, then 4PHR or less TiO₂ can be used in the polycarbonate compositions (EX 24-EX26 vs. EX 27-EX 29).

The data in Table 7 shows the effect of TiO₂ on the smoke densityperformance of a composition with and without poly(siloxane-carbonate)present.

TABLE 7 Component, Properties CEX 10 EX 30 TBBPA-BPA Copolymer 40.0 40.0SiPC 4 0.00 50.00 PC 1 60.0 10.0 TiO₂ 2.0 2.0 IRGAPHOS 168 0.060 0.060Formulated Blend Composition Total wt % Siloxane 0 3 Total wt % Bromine10.4 10.4 MVR-6 min 17.7 9.5 MVR-18 min 18.6 10.4 MVR, % Change 5.1 9.6Tg 160 161 NI-125 RT Ductility 0.0 100.0 J/m 87.7 467.0 ft-lbs/in 1.68.7 MAI-RT Ductility 100 100 Energy to max load-Average J 72 70 Energyto failure-Average J 76 76 Energy, Total-Average J 76 76 Density-Avgg/cc 1.304 1.293 Specific Gravity-Average 1.308 1.296 FAA Smoke DensityAverage 231.0 72.0 Ds at 4 min Standard deviation 78.2 43.6

The results in Table 7 show that the ability ofpoly(siloxane-carbonate)s in the compositions to reduce smoke is notdiminished by the presence of TiO₂ in the compositions, even though itis known in the art that TiO₂ can improve polycarbonate flameperformance. Even with 2 PHR TiO₂ present, without anypoly(siloxane-carbonate), CEX 10 does not pass the DsMax smoke target ofless than 200, having a value of 231. By contrast EX 30 (withpoly(siloxane-carbonate) present) passes the DsMax test target value ofless than 200 with a value of only 72.

Furthermore the impact performance of molded parts from compositionscontaining TiO₂ is improved by the presence of apoly(siloxane-carbonate) as illustrated by Ex 24-29 in Table 6 and EX 30in Table 7 (which show 100% ductility performance at room temperature)while CEX 10 has 0% ductility performance at room temperature.

Density of Low OSU Heat Release, Low Smoke Polycarbonate Compositions.

The density results in Tables 3-5 illustrate the factors that moststrongly affect the density of the compositions that do not containtitanium dioxide. The strongest influence on density is the wt % ofbromine in the polycarbonate compositions. For example in CEX 2, 3, 4,5, and 6 in Table 3 the wt % bromine increases from 0 to 13 wt % and thedensity increases from 1.198 to 1.315 g/cc. A similar trend is shown inTable 4 where the wt % bromine increases from 0 to 26 wt % and thedensity increases from 1.183 to 1.450 g/cc. The results in Table 5 abovealso illustrate that increasing the amount of siloxane in thecompositions does slightly decrease the density in the compositions. Forexample, the wt % bromine is the same in CEX 10 and EX 13-EX 15 at 10.4wt %, but the wt % siloxane increases from 0 to 2.0 wt % and the densitydecreases from 1.291 to 1.277 g/cc. The chain length of siloxane or thewt % siloxane in the poly(siloxane-carbonate) does not show a largeinfluence in the density based on the results in Table 5. In order toobtain a density below the targeted maximum density of 1.320 g/cc foraircraft applications, it appears that less than 15 wt % bromine can beused.

The presence of titanium dioxide further increases the density of thecompositions as illustrated in Table 6. In Table 6, compositions areshown having 3.0 wt % siloxane and 10.4 wt % bromine contents andincreasing amounts of titanium dioxide. In EX 23-29 the wt % titaniumdioxide increases from 0 wt % to 7 wt % and the density increases from1.278 to 1.340 g/cc. Therefore in order to achieve a maximum density ofless than 1.320 g/cc, less than 5 wt % titanium dioxide can be used inthe compositions shown in Table 6.

Combining the results from the various Tables shows achieving thetargeted density maximum of 1.320 g/cc for aircraft applications can beaccomplished by balancing the amount of titanium dioxide with the amountof brominated copolycarbonate. Bromine contents of less than 13 wt % andtitanium contents of less than 5 wt % can be used to meet the aircraftdensity targets for white product compositions (EX 24-EX 27 vs. EX 28-EX29).

Alternative Bromine Sources.

Property comparisons were made between polycarbonate compositions havingsimilar wt % polysiloxane and similar wt % bromine in the compositionsusing three different bromine-containing additives, in particular abrominated epoxy oligomer (F3100 from ICL Industrial Products, EX 30), abrominated polycarbonate oligomer (BC52, EX 31) and a brominatedcopolycarbonate (TBBPA-BPA copolymer, EX 32). Results are in Table 8.

TABLE 8 Components EX 31 EX 32 EX 33 SiPC 4 50.0 50.0 50.0 PC 2 30.7030.00 20.00 F-3100 19.300 — — BC52 — 20.0 — TBBPA-BPA Copolymer — —40.000 Phosphite 0.060 0.060 0.060 Mw of Br compound 15,000 2,665 22,500Softening Temp C. 200 171 182 Total Formulation % Siloxane 3 3 2.7 %Bromine 10.4 10.4 9.5 D length 45.0 45.0 45.0 Properties MVR-6 15.7 11.88.3 % Change 17.5 4.9 11.9 Tg 146.5 151.4 159.8 NI-125 RT Ductility100.00 0.0 100.0 J/m 773.0 123.0 744.0 ft-lbs/in 14.5 2.3 13.9 MAI-RTDuctility 100.0 100.0 100.0 Energy to max load-Avg J 68.1 75.1 78.4Energy to failure-Avg J 72.6 79.8 85.0 Energy, Total-Avg J 72.6 79.885.1 Density-Avg g/cc 1.282 1.273 1.268 Specific Gravity-Avg 1.285 1.2761.271 HDT-ASTM-G 1.8 MPa 123.8 127.7 135.2 HDT-ASTM-G 0.455 MPa OSU 2min. TTF 42.4 30.1 36.4 45.8 24.0 26.2 33.8 21.8 18.2 Average 40.7 25.326.9 Standard deviation 6.2 4.3 9.1 OSU Peak 50.5 50.5 60.3 50.8 43.149.5 59.5 60.2 54.6 Average 53.6 51.3 54.8 Standard deviation 5.1 8.65.4 FAA Smoke Density Ds at 4 min 96.6 23.81 20.5 66.3 35.3 18.2 88.616.6 42.7 Average 83.8 26.0 27.1 Standard deviation 15.7 13.2 13.5 Dmax96.8 23.81 20.5 66.3 35.3 18.2 88.6 16.6 42.7 Ave 83.9 26.0 27.1Standard deviation 15.7 13.2 13.5 Optical Properties % T at 125 mil (3.2mm) 22.0 78.7 77.3 YI 62.7 19.1 19.8 % Haze 102.6 7.3 6.5

The results in Table 8 show that the targeted flame and smoke properties(2-min total heat release and peak heat values of less than 65 and asmoke Dmax value of less than 200) were achieved in polycarbonatecompositions containing siloxane using the different sources of bromineas flame retardants. The high impact values in EX 31 (100% ductility inthe notched Izod test) as compared to EX 32, illustrates the importanceof selecting a bromine composition with an M_(W) of at leastapproximately 15,000 when formulations of high toughness are needed.High transparency (greater than 75%) and low haze (less than 10%) werealso found with EX 32. In addition, all three of the compositions showeddensity values below the 1.320 g/cc upper limit.

Other Additives

The effect of additives often used as flame retardants in polycarbonate,on the smoke density properties of compositions made from combinationsof the poly(siloxane-carbonate) and brominated copolycarbonate, werealso investigated and the results are shown in Table 9.

When used at levels commonly employed to improve flame performance,improve the color stability, or reduce haze in polycarbonates, theadditives showed no effect on the flame retardant performance of thepolycarbonate compositions. EX 34 (with TiO₂) possessed a similarD_(max) value to EX 35-39 (with the flame retardant, colorstabilization, or haze reducing additives) (EX 34 had a D_(max) of 21,whereas the highest D_(max) values measured for the compositions ofTable 9 was 29).

TABLE 9 Name EX 34 EX 35 EX 36 EX 37 EX 38 EX 39 TBBPA-BPA 40.0 40.040.0 40.0 40.0 40.0 SiPC 4 50.00 50.00 50.00 50.00 50.00 50.00 PC 1 10.010.0 10.0 10.0 10.0 10.0 KSS — 0.30 — — — — KSS — 0.30 — — — — Rimarsalt — — 0.08 0.08 — — Octaphenylcyclotetrasiloxane — — — 0.10 — — STB —— — — 0.75 — Phosphorus acid solution (0.15%) — — — — — 0.10 TiO₂ 2.002.00 2.00 2.00 2.00 2.00 Phosphite 0.06 0.06 0.06 0.06 0.06 0.06 TotalFormulation Wt % Siloxane 3.0 3.0 3.0 3.0 3.0 3.0 Wt % Bromine 10.4 10.410.4 10.4 10.4 10.4 Properties MVR-6 Cc/10 min 9.6 10.0 12.4 13.6 10.49.9 Tg ° C. 159 157 160 159 160 160 NI-125 RT Ductility 100 100 100 1000 100 J/m 588.0 544.0 534.0 596.0 143.0 498.0 ft-lbs/in 11.0 10.2 10.0.11.2 2.7 9.3 Density-Avg g/cc 1.287 1.291 1.291 1.288 1.293 1.291Specific Gravity-Avg 1.290 1.294 1.294 1.291 1.296 1.294 HDT-ASTM-G 1.8MPa 134 134 134 134 134 135Other Silicone-Containing Additives.

The impact of replacing the poly(siloxane-carbonate) with othersilicone-containing additives was also investigated and the resultsshown in Table 10.

TABLE 10 Components CEX 11 CEX 12 CEX 13 CEX 14 TBBPA-BPA 30.00 30.0030.00 30.00 PC 2 70.00 69.50 69.50 69.50 DF1040 0.50 OPTS 0.50 D4 0.500Phosphite 0.060 0.060 0.060 0.060 Total Formulation Wt % 0 0.5 0.5 0.5Siloxane Wt % 7.8 7.8 7.8 7.8 Bromine Properties MVR-6 5.5 5.9 5.5 5.6NI-125 RT Ductility 0.0 0.0 0.0 0.0 J/m 139 148 132 135 ft-lbs/in 2.62.8 2.5 2.5 Density-Avg g/cc 1.262 1.263 1.264 1.264 SpecificGravity-Avg 1.265 1.267 1.267 1.267 HDT-ASTM-G 1.8 MPa 136 135 136 135OSU Test FAR25.853 (d) Appendix F, Part IV 2 Min OSU Average 17 59 19 28Standard 9.7 2.6 20.2 15.9 deviation Peak OSU Average 60 75 65 65Standard 4.5 4.0 3.8 8.7 deviation NBS Smoke Density (ASTM F814/E662,Flaming Mode) DS Max Ave 529 306 521 406 Standard 84 197 219 199deviation

The results in Table 10 show that none of the siloxane sources performedas well as the poly(siloxane-carbonate) of the invention. The resultsfor EX 3 and EX 4 from Table 3 (with 0.4 wt % polysiloxane content andeither 7.8 or 10 wt % bromine) show that both pass the OSU heat releaseand smoke tests, with values less than 65 for the OSU tests and lessthan 200 for the smoke tests. In contrast CEX 12, 13, and 14 haveslightly higher amounts of siloxane (0.5 wt %) and the same amount ofbromine (7.8 wt %) and fail the smoke tests with DsMax values of 300 orgreater. These other sources of silicone are therefore much lesseffective at suppressing smoke in the smoke tests thanpoly(siloxane-carbonate) described herein. While not wishing to be boundby any specific theory, it is believed that providing the siloxane in aless volatile, less mobile (higher Tg), high molecular weight polymercould help to maintain the siloxane in the composition longer and keepthe siloxane better dispersed during burning.

Color Stability and Weathering Performance.

Materials used in the transportation industry, especially those thatpass the OSU and DsMax smoke requirements, often have poor stabilitywhen exposed to outdoors light. Thus manufactures must either paint thefinished part or risk the yellowing or other discoloration of the parts.In order to demonstrate the improved color stability performance of thepoly(siloxane-carbonate) and brominated copolycarbonate compositionsover those found in art, the compositions were formulated with andwithout UV stabilization additives in a bright white color package.These compositions and results are shown in Table 11.

TABLE 11 Component EX 40 EX 41 EX 42 EX 43 TBBPA-BPA 40.0 40.0 40.0 40.0SiPC 4 50.00 50.00 50.00 50.00 PC 1 10.0 10.0 10.0 10.0 Tinuvin 1577 00.3 — — UVA 234 — 0.300 — Cyasorb 3638 — — — 0.3 TiO₂ 2.0 2.0 2.0 2.00.060 0.060 0.060 0.060 Total Formulation Total wt % 3.00 3.00 3.00 3.00Siloxane Total wt % 10.4 10.4 10.4 10.4 Bromine Properties MVR-6 minutes8.9 8.7 9.4 9.0 MVR-18 minutes 8.9 11.2 10.6 9.0 NI-125 RT Ductility 100100 100 100 J/m 566 542 539 525 ft-lbs/in 10.6 10.1 10.1 9.8 OSU 2 min.TTF 26.0 21.3 23.0 18.3 60 mil 19.0 17.6 25.1 21.6 21.0 23.8 25.7 23.4Average 22.0 20.9 24.6 21.1 Standard 3.6 3.1 1.4 2.6 Deviation OSU TTF44.0 44.7 45.1 38.4 60 mil 43.2 41.8 47.3 49.4 44.5 43.0 44.3 48.3Average 43.9 43.2 45.6 45.3 Standard 0.7 1.5 1.5 6.0 Deviation FAA SmokeDe TTF 11.5 16.4 21.1 25.00 Ds at 4 minutes 60 mil 10.7 16.8 22.0 22.511.5 27.3 23.5 20.8 Ave 11.2 20.2 22.2 22.8 Standard 0.4 6.2 1.2 2.1Deviation DsMax TTF 11.5 16.4 21.3 25.0 60 mil 10.7 16.8 22.0 22.5 11.527.3 23.5 20.8 Ave 11.2 20.2 22.3 22.8 Standard 0.4 6.2 1.1 2.1Deviation

All of the compositions were 100% ductile in notched Izod testing, havea density requirement of less than 1.320 g/cc (data not shown), and allshowed passing values in the OSU heat release and smoke testing, withOSU values below 65 and smoke D_(max) values below 200.

Bright white sample plaques were placed on a 45 degree angle southfacing rack exposed to an unobstructed sunlight light exposure for 466hours and then tested for a color shift by measuring the reflected lightof the light-exposed plaques using a spectrophotometer. The colorstability/weathering results are shown in Table 12.

TABLE 12 EX 41 EX 43 Outdoor Comparative (a) EX 40 Tinuvin EX 42 CyasorbExposure, No UVA No UVA 1577 UVA234 3638 Hrs DE DE DE DE DE 0 — — — — —110 5.9 0.3 0.3 0.5 0.5 466 7.9 0.7 0.6 0.4 0.3 (a) White Lexan* FST9705plaque. * Trademark of SABIC Innovative Plastics IP BV

All four of the samples (EX40-43) of the present invention have bettercolor stability than the existing commercial OSU comparative resin. Allthree of the samples containing UV stabilizing additives showed evenlower tendency to yellow as determined by lower DE values than thecomparative sample or the sample with no UV stabilizers, even after 466hours. The benefits in color stability of the compositions of thepresent invention compared to a composition that has comparable OSUsmoke and flame performance but employs polyarylatepoly(siloxane-carbonate)s in the composition (LEXAN* FST 9705 polymer)is also illustrated by comparing the DE values of EX 40 with FST 9705after 466 hours of weathering (neither sample contained UV stabilizationadditive). The FST 9705 showed much higher DE values than CEX 15 (DE 7.9vs. 0.7).

Ranges disclosed herein are inclusive and combinable (e.g., ranges of“up to 25 wt %, or, more specifically, 5 wt % to 20 wt %,” is inclusiveof the endpoints and all intermediate values of the ranges of “5 wt % to25 wt %,” etc.). “Combination” is inclusive of compositions, blends,mixtures, alloys, reaction products, and the like. Furthermore, theterms “first,” “second,” and the like do not denote any order, quantity,or importance, but rather are used to distinguish one element fromanother, and the terms “a” and “an” herein do not denote a limitation ofquantity, but rather denote the presence of at least one of thereferenced item. Reference throughout the specification to “anembodiment”, “another embodiment”, “an embodiment,” and so forth, meansthat a particular element (e.g., feature, formula, and/orcharacteristic) described in connection with the embodiment is includedin at least an embodiment described herein, and can or cannot be presentin other embodiments. In addition, it is to be understood that thedescribed elements can be combined in any suitable manner in the variousembodiments. The suffix “(s)” as used herein is intended to include boththe singular and the plural of the term that it modifies, therebyincluding at least one of that term (e.g., the colorant(s) includes atleast one colorants).

Compounds are described using standard nomenclature. For example, anyposition not substituted by any indicated group is understood to haveits valency filled by a bond as indicated, or a hydrogen atom. A dash(“-”) that is not between two letters or symbols is used to indicate apoint of attachment for a substituent. For example, —CHO is attachedthrough carbon of the carbonyl group. The term “alkyl” includes bothC₁₋₃₀ branched and straight chain, unsaturated aliphatic hydrocarbongroups having the specified number of carbon atoms. Examples of alkylinclude, but are not limited to, methyl, ethyl, n-propyl, i-propyl,n-butyl, s-butyl, t-butyl, n-pentyl, s-pentyl, n- and s-hexyl, n- ands-heptyl, and, n- and s-octyl. The term “aryl” means an aromatic moietycontaining the specified number of carbon atoms, such as to phenyl,tropone, indanyl, or naphthyl. The term “hydrocarbon group” encompassesgroups containing the specified number of carbon atoms and havingcarbon, hydrogen, and optionally one to three heteroatoms selected fromO, S, P, and N. Hydrocarbon groups can contain saturated, unsaturated,or aromatic moieties, or a combination comprising any of the foregoing,e.g., an alkyl moiety and an aromatic moiety. The term “aromatic group”includes groups having an aromatic moiety, optionally together with asaturated or unsaturated moiety.

All cited patents, patent applications, and other references areincorporated herein by reference in their entirety. However, if a termin the present application contradicts or conflicts with a term in theincorporated reference, the term from the present application takesprecedence over the conflicting term from the incorporated reference.

While the invention has been described with reference to embodiments, itwill be understood by those skilled in the art that various changes canbe made and equivalents can be substituted for elements thereof withoutdeparting from the scope of the invention. In addition, manymodifications can be made to adapt a particular situation or material tothe teachings of the invention without departing from essential scopethereof. Therefore, it is intended that the invention not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this invention, but that the invention will include allembodiments falling within the scope of the appended claims.

We claim:
 1. A composition comprising: a first polycarbonate comprisinga poly(siloxane-carbonate) derived from at least one dihydroxy aromaticcompound of formula (5)

and at least one polysiloxane bisphenol of formula (1) or formula (2)

wherein each of R^(a) and R^(b) is independently a halogen atom or amonovalent hydrocarbon group, p and q are each independently integers of0 to 4, X^(a) represents a single bond or one of the groups of formulas(6) or (7),

wherein each R^(c) and R^(d) is independently hydrogen, C₁₋₁₂ alkyl,C₁₋₁₂ cycloalkyl, C₇₋₁₂ arylalkyl, C₁₋₁₂ heteroalkyl, or cyclic C₇₋₁₂heteroarylalkyl, and R^(e) is a divalent C₁₋₁₂ hydrocarbon group, R iseach independently a C₁-C₃₀ hydrocarbon group, Ar is each independentlya C₆-C₃₀ aromatic group, R² is each independently a C₇-C₃₀ hydrocarbongroup, and E in formula (1) and formula (2) has an average value of 10to 200; a brominated oligomer different from the first polycarbonate,wherein the brominated oligomer has a weight average molecular weight ofless than 18,000 Daltons as measured by gel permeation chromatographyusing polystyrene standards; and optionally, an additional polycarbonatedifferent from the first polycarbonate and the brominated oligomer;wherein the composition is free of copolymers comprising carbonate unitsand ester units; and wherein the wt % of the first polycarbonate,brominated oligomer, and optional additional polycarbonate sum to 100 wt%, each of the wt % of the first polycarbonate, brominated oligomer, andoptional additional polycarbonate is based on the sum of the weights ofthe first polycarbonate, brominated oligomer, and optional additionalpolycarbonate; the first polycarbonate is present in an amount effectiveto provide the siloxane units of the first polycarbonate in an amount ofat least 0.4 wt %, based on the sum of the wt % of the firstpolycarbonate, brominated oligomer, and optional additionalpolycarbonate, and the brominated oligomer is present in an amounteffective to provide the bromine of the brominated oligomer in an amountof at least 7.8 wt %, based on the sum of the wt % of the firstpolycarbonate, brominated oligomer, and optional additionalpolycarbonate; and further wherein an article molded from thecomposition has an OSU integrated 2 minute heat release test value ofless than 65 kW-min/m² and a peak heat release rate of less than 65kW/m² as measured using the method of FAR F25.4, in accordance withFederal Aviation Regulation FAR 25.853 (d), and an E662 smoke test Dmaxvalue of less than 200 when tested at a thickness of 1.6 mM.
 2. Thecomposition of claim 1, wherein the first polycarbonate is present in anamount of at least 10 wt %, the brominated oligomer is present in anamount of at least 15 wt %, each based on the sum of the wt % of thefirst polycarbonate, the brominated oligomer, and the optionaladditional polycarbonate.
 3. The composition of claim 2 wherein thedihydroxy aromatic compound of the first polycarbonate is Bisphenol-A.4. The composition of claim 1 wherein the polysiloxane bisphenol (1) hasthe formula:


5. The composition of claim 4 wherein the dihydroxy aromatic compound ofthe first polycarbonate is Bisphenol-A.
 6. The composition of claim 1wherein the polysiloxane bisphenol (2) has the formula:


7. The composition of claim 1 wherein the siloxane units of the firstpolycarbonate are present in an amount of between 1.5 and 3.5 wt % basedon the sum of the wt % of the first polycarbonate, the brominatedoligomer and the optional additional polycarbonate, the bromine of thebrominated oligomer is present in an amount of between 7.8 and 13 wt %based on the sum of the wt % of the first polycarbonate, the brominatedoligomer and the optional additional polycarbonate; and the additionalpolycarbonate is present in an amount of 8 to 50 wt % based on the sumof the first polycarbonate, the brominated oligomer and the additionalpolycarbonate.
 8. The composition of claim 1, wherein the brominatedoligomer comprises repeat units derived from Bisphenol-A.
 9. Thecomposition of claim 8, wherein the brominated oligomer comprises 25 to35 mol % of units derived from 2,2′6,6′tetrabromo-4,4′-isopropylidenediphenol and 65 to 75 mole % of unitsderived from Bisphenol-A.
 10. The composition of claim 1 wherein thecomposition has a density of less than 1.31 g/cc.
 11. The composition ofclaim 10 wherein the composition has a density of less than 1.30 g/cc.12. The composition of claim 1 wherein the E662 smoke test Dmax has avalue of less than 100 when tested at a thickness of 1.6 mm.
 13. Thecomposition of claim 1, wherein an article molded from the compositionhas a room temperature notched Izod impact of greater than 500 μm asmeasured according to ASTM D 256-10 at a 3.2 mm thickness.
 14. Thecomposition of claim 13 wherein the E662 smoke test Dmax has a value ofless than 100 when tested at a thickness of 1.6 mm.
 15. The compositionof claim 1, wherein an article molded from the composition has a hazeless of less than 15% and a transmission greater than 75%, each measuredusing the color space CIE1931 (Illuminant C and a 2° observer) at a 3.2mm thickness.
 16. The composition of claim 15, wherein an article moldedfrom the composition has a room temperature notched Izod impact ofgreater than 500 μm as measured according to ASTM D 256-10 at a 3.2 mmthickness.
 17. The composition of claim 1 wherein the brominatedoligomer is a brominated polycarbonate oligomer.
 18. The composition ofclaim 1 wherein the brominated oligomer is a brominated epoxy oligomer.19. The composition of claim 1, further comprising 0.5 to 3 parts byweight of titanium dioxide per hundred parts by weight of thecombination of the first polycarbonate, brominated oligomer, andoptional additional polycarbonate.
 20. The composition of claim 1,wherein the composition is substantially free of a fluorinatedpolyolefin encapsulated by poly(styrene-acrylonitrile).
 21. Thecomposition of claim 1 wherein the difference in the melt volume flowrate of the composition at 300° C. at 6 minutes and 18 minutes is lessthan 10%, wherein melt volume flow rate is determined at 300° C. under aload of 1.2 Kg through a 2.1 mm diameter×8 mm long orifice.
 22. Anarticle selected from a molded article, a thermoformed article, a foamedarticle, an extruded film, an extruded sheet, one or more layers of amulti-layer article, a substrate for a coated article or a substrate fora metallized article made from the composition of claim
 1. 23. Thearticle of claim 22, wherein the article is a component of an aircraftinterior or a train interior.
 24. The article of claim 23, wherein thearticle is selected from an access panel, access door, air flowregulator, air gasper, air grille, arm rest, baggage storage door,balcony component, cabinet wall, ceiling panel, door pull, door handle,duct housing, enclosure for an electronic device, equipment housing,equipment panel, floor panel, food cart, food tray, galley surface,handle, housing for television, light panel, magazine rack, telephonehousing, partition, part for trolley cart, seat back, seat component,railing component, seat housing, shelve, side wall, speaker housing,storage compartment, storage housing, toilet seat, tray table, tray,trim panel, window molding, window slide, or window.
 25. The article ofclaim 24, wherein the article is selected from a balcony component,baluster, ceiling panel, cover for a life vest, cover for a storage bin,dust cover for a window, layer of an electrochromic device, lens for atelevision, electronic display, gauge, or instrument panel, light cover,light diffuser, light tube, light pipes, mirror, partition, railing,refrigerator door, shower door, sink bowl, trolley cart container,trolley cart side panel, or window.
 26. The composition of claim 1,wherein the brominated oligomer has a bromine content of 40 to 60 wt %.27. The composition of claim 1, wherein the brominated oligomer has abromine content of 45 to 55 wt %.
 28. The composition of claim 1,wherein the brominated oligomer has a bromine content of 50 to 55 wt %.29. The composition of claim 1, wherein the brominated oligomer has aweight average molecular weight of 2,000 to 15,000 Daltons as measuredby gel permeation chromatography using polystyrene standards.
 30. Thecomposition of claim 1, wherein the brominated oligomer has a weightaverage molecular weight of 3,000 to 12,000 Daltons as measured by gelpermeation chromatography using polystyrene standards.
 31. Thecomposition of claim 1, wherein the brominated oligomer is present in anamount effective to provide the bromine of the brominated oligomer in anamount of 7.8 to 14 wt %, based on the sum of the wt % of the firstpolycarbonate, brominated oligomer, and optional additionalpolycarbonate.
 32. The composition of claim 1, wherein the brominatedoligomer is present in an amount effective to provide the bromine of thebrominated oligomer in an amount of 8 to 12 wt %, based on the sum ofthe wt % of the first polycarbonate, brominated oligomer, and optionaladditional polycarbonate.